Some snakes are stubborn when switching to f/t but only a few never make the transition. Sometimes it takes a lot of patience and a little tough love but if you only offer f/t the animal will eat eventually. I have yet to see a healthy animal starve itself to death when food was consistently offered. I agree with super heating the prey item with a hairdryer and trying the zombie dance. Those things have worked for me in the past. You can also try leaving the prey item in overnight. I have one snake that won't take food from the tongs. I have to leave her food in the enclosure overnight and it's always gone by morning.