I sold a littler of 4 puppies on the 18th I met everyone at least 3 times before they went home with a pup, on older couple (40s) asked if I could keep the pup till the 22rd as they where both working but one would have 2 weeks off after the 23rd and the other 3 weeks so they could give their full attention to the pups, my pups have been brought up with 2 cats (one 4months other 1 year) they play and interact with the cats all most all of the time, as this couple had a 2 year old cat they thought it would be perfect. But they messaged me yesterday (Christmas) saying they wanted to bring her back as the cat has refused to come in the home since the pup has been brought in. I said if at any point in the future you become unable to look after her I would always be willing to give her a home with me. But I never said anything about money as I have never had a pup back and definitely didn't expect one back after under a week. Do I give a full refund minus the deposit? Half? None?
There is nothing wrong with the pup just owners don't want to try to teach the cat and the pup about each other.
Before they took her home I went over how to introduce an existing pet to a new one but it doesn't seem like they did anything I said.

Just to add I am unsure about selling the pup on as I don't want her to stress about the constant changing of people and situations. Should I keep her? Sell her on?

Annoying, especially as you seem to have done all the homework, checking the new owners.  But getting her back, and fast, is surely the most important thing now, so as it's also not long since she left you, I'd make them a full refund.   As for selling her or keeping her, I'd imagine that after such a short period of time away, she should be okay to find another good home for.   BUT only you can assess what's gone on, how she is and so on.   A vet check might be worth considering, after a few days back 'home'.

And I'd be aware re her bringing infection/external parasites back to any puppies you still have from that litter?

ps    As I did with an older puppy I decided to home after running her on for a while and thinking she wasn't really up to 'keeper' standard, I made a full refund (although the people had her at a fraction of what she'd have cost at 8 - 10 weeks) less a 'boarding fee' (again a few pounds a day only) for the time I had her back before a new home appeared.   I did this, and might not have, had the reason I had to go rescue her and bring her back not been so bad, to try to make the people who bought her think more carefully about what having a dog actually meant before doing it again!

Had exactly the same scenario as you, when I bred my last litter 7 years ago!. A couple bought a puppy from me on a Saturday and asked to bring her back the next day as she was chasing their cat. Like you I had explained about puppies will chase cats, even though mine were brought up with them. Although I felt that 1 night wasn't really long enough to give her a chance, I was thankful to have her back as felt that if they gave up so easily there would be other episodes and she would be older and possibly settled.... Luckily I had several people who had been waiting for a puppy so she was easily rehomed and is a much loved companion in a lovely home. As to the money I gave the original owners a total refund, I don't ask for deposits. Hope this helps.

I'm away for family at the moment for Christmas, I am back tomorrow at 10 and getting her at 11, so 100% I am getting her back. But the buyer gas not mentioned money yet so I just wanted to know what people thought before bringing it up myself.
Also just mum,dad in the house plus the 2 cats, all wormed and flead with pups a week and half ago so won't be able to give them any more for 3 weeks

I went and collected a pup after 2 weeks.  I had the full refund in my hand ready to give the woman, even though she had not mentioned money.  I just wanted to remove my pup from a home not willing to work with a youngster. 

I kept her. 

Regarding a refund at this age and circs I would give a full refund. I would then look to find her a new home when I felt I was ready if I decided not to keep her myself but first and foremost I would get the puppy and give a full refund.

As it's such a short time,  if pups still under 10 weeks (I consider that 8-10 weeks is normal homing period),  then full refund and contact someone else on your waiting list.

Keep the deposit if you have to re-advertise.

If pup were older I'd refund after sale and deduct expenses for advertising and an amount for boarding.  I charge £25 a week past 10 weeks.

I agree with what's been said in the above posts (full refund etc etc).
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Also, don't give them a full refund until you have checked with The Kennel Club that the pup is still registered in your name, although they may give you the paperwork back, they could have still already registered online, which may become another headache for you ....? Just a thought.

I think there is plenty of time to find a more loving & understanding home for your puppy and I would follow Brainless advice above.

I brought my puppy home and had 2 cats.  One cat refused to come in for a week! I went out to encourage, feed cat. Said cat would come in if puppy behind closed lounge door. I fed hum upstairs so he had space and freedom from dog. Took him six months to walk in house with dog in kitchen. Roll on three years and cat walks past dog, rubs face with dog... Runs to meet us outside if walking home.
Not once did I think RETURN puppy! I chose to have puppy after cats, researched and expected a few teething problems. A stair gate worked wonders on stairs and kitchen. Still have on stairs....

I think I'd give a full refund but advise they don't get another puppy! As puppy still young I'd try find new home possibly off your reserve list?

> don't give them a full refund until you have checked with The Kennel Club that the pup is still registered in your name, although they may give you the paperwork back

You know something, I was so worried about my pup that I didn't even think of her paperwork - I left the sack of food, tins of food, new bed, collar and lead, everything from the puppy pack.  Although I still have her and she's never had a litter, so KC papers not so important.  I look back now and think what a total bozo I must have been not to think about anything except my pup.

But hey, she's still here, spayed now, and much adored. 

But it would have been an issue if you hadn't intended keeping her,  or had wanted to breed from her.

A friend had the devils own job to get the short term owners to sign and return reg papers,  so she could pass them to final owners.