
Well done for perseverance and success.
Why someone would think that because you didn't want to show then you shouldn't have what you paid for .. ie KC registration I can't understand. It is worth complaining to the KC - when I bought my first puppy many years ago like you I was promised KC registration. It didn't arrive and when I contacted the KC I was told that due to non-registration the breeder had been banned for 10 years, so I wasn't going to get her registration. I didn't bother going to the small claims because so many people had I wasn't going to get any money, nor was I going to get the registration I'd paid for. As a 'pet' owner I had to register her on the working register so I could complete in agility with her. There's more than showing that needs registration and there's also you should get what you paid for!
Of course, now you would realise that at 6 weeks you wouldn't get a pup who'd been vaccinated...but then they shouldn't have been advertised as having been - but of course you shouldn't have had the pup for another couple of weeks. My pups usually leave at 7 or 8 weeks and then the owner can take them for a vet check and first innoculation. I recommend no worming or flea treatment the day of innoculations - I gear the worming up to be 9 and 11 weeks so the pup doesn't get overloaded - it's a lot for an immune system to cope with. It's very difficult to find good breeders but coming on here will help with that. I learnt a lot from my first puppy purchase, but never for one moment regretted having her - she was a one in a million dog :-)
Penny