My Burmese is a live only feeder, it happens from time to time. No feeding response at all to f/t and will only get excited for live rats. I have to drive 50 miles round trip each week to get his food simply because that's the only option for me. You may be in the same situation, and its just something you'll have to learn to work around. Please check all local laws regarding Burmese pythons, and ensure that you have all permits required, and that they are allowed within your city (many cities have ordinances against such species).

Burmese will also go off of food if they are not met with optimal conditions in their cage. Can you give a little more indication of what the husbandry is like so we can access if there is a problem here? You say its a rescue, but where did you "rescue" it from? I have a good bit of experience with problem feeders and giants, so feel free to PM me if you need help or feel odd posting anything.

Cheers, and good luck