At this point, you're doing all you can. If they won't let you feed it live, its possible it will never eat on its own if its going to be a live feeder. IMO the onus is on them to care for it. If they're not willing to, then its there loss.

At this point, I think it would be highly irresponsible for them to even sell the snake. They should just give it to you. If it isn't feeding f/t on its own by now, it might never, or at least without going through live.

You need to talk to your manager or whoever is in charge about this. Are they going to just force feed it forever? How do they expect to sell a snake that can only be force fed? Let alone selling such a sickly snake.

Call me cruel, but some just aren't meant to make it. At some point, that is something you're going to have to weigh IMO.