Help Pay Hamilton's Bills

Hamilton stopped eating and going to the bathroom so I took him to the vet. We assumed he was blocked and he was given enemas and kept for observation. Two days later he still wasn't improving, so the Dr. did x-rays that showed "a mass" in the colon. He suggested an ultrasound to confirm and said the ultrasound specialist saw something and recommended surgery. The only thing found was a thickened abdominal wall which they chose to biopsy. Two days after coming home from surgery he developed a fever and a lump on his stomach. I took him to another vet who reviewed all the records including the biopsy results and determined there was most likely no reason for the initial surgery - the mysterious "mass" was never found, the biopsy showed absolutely nothing wrong, and the lump was from the sutures being tied too tightly around the abdominal muscle. A new plan of prednisone, pain meds, and anti-biotics showed vast improvement in just three days' time. It also helped him cough up a huge hairball - probably the culprit. Unfortunately, Hamilton went through all this for probably no good reason, and I'm not only left with the guilt of putting him through it, but the bills to pay for what was most likely an unnecessary surgery and resulting issues. :( Any help you can offer would be greatly appreciated.