
So sorry to hear this. Unfortunately some speciallists see insurance as a way to make money, I object when the vet asks if the dog is insured before starting treatment, that seems like an awful lot of money.
My Mum's dachsie was diagnosed and treated by the University Vet Centre for a Liver Shunt it,the pre op investigation/ care, surgery, post op care and follow up bloods for 6 months only came to just over £5,000, we always saw the chap who had operated on her, he couldn't find anyone in the country who had treated a dachsie for this condition so was eager to see how she got on, she was 9 back in May.
I think it is time for a second opinion, they shouldn't have been railroaded into making a decision, it wasn't a life and death situation after all, now it has gone seriously wrong due to mismanagement and inability to see a major problem leading to pain and suffering for the dog. Complain to who ever is in charge at the speciallist vets, you have been paying for speciallist care but not getting it,tell them the insurance has reached its limit due to the extra costs involved for treatment, don't know if the insurance company can be approached as to whether the costs have been excessive compared with their knowledge of similar conditions and treatment, you may get a refund or no further charge although I would be reluctant to take him back there.
I hope the infection settles and doesn't leave the leg worse than it was before.