I'm sorry to hear thisWhat meds/laxatives did the vet try?
I had a corn snake who the vet thought was backed up/impacted, and she ended up being egg bound from when she was paired over two years previous with the last owner. We gave Baytril shots, mineral oil inserted down into her belly to try to help her pass the "blockage" and he gave a warm water enema before we figured it was a different problem. Did your vet try any of these?