oreo surgery

oreo was the victim of a hit and run.his back leg was badly broken.his bill came to 2600.00 ive paid some. but still have 1000.00 due.oreos family gave him up.he has a potential new family but i dont want to have him start his new life owing  money for medical bills. im his foster mom. because oreos leg kept swelling we took him once again to his vet , he claimed oreo was healing just fine. i didnt feel comfortable with this .so i took him to a specialist that informed me the bone never healed and that his leg from his knee to his hip was infected due to the first surgery, in order to heal he now needs a bone graft and a bone plate and several antibiotics the infection was heading to his heart . he needed surgery right away at an additional 4555.00. if you would like to check our story , you may call the vet ,, the number is 310 -575-5656 . this surgery was billed on a care card . i only have 6 months to pay it off. if you can help in any way it would be appreciated. please share his story.. thanks