
What a tragic thing to happen. :( I'm so sorry for you. :(
The next practical thing is to consider asking your vet if he knows of any puppies needing a foster mum - to give your bitch a 'family' to look after. Okay, they're not hers, but she won't mind. If not you'll need to get her out and about and active to prevent too much milk production and avoid masitis. Put her on a low-protein food and give her plenty of exercise. Don't allow her to brood. It seems harsh but it's better for her mental and physical health.
Regarding the stud fee, you'll have to contact the stud owner.
Technically the mating was successful in that it resulted in a pregnancy, but most people would be sympathetic to this particular situation.
Edit: just seen your last post. It's good news that the stud owners are reasonable people. Good luck when and if you have another go. :)