In the majority of cases when a young animal refuses to eat for a new owner it's often husbandry related.
The more info you will give the better people will be able to guide you to help you with this issue.
How big is the BP?
How big is his enclosure?
What are the temps? and what type of thermometer do you measure them with? ( Digital or analog?)
Do you provide tight identical hides with all sides touching the BP's body?
How often as this BP been handled?
What was he previously feeding on?
A young BP should really not be house in something much larger than 6 or 15 quarts tub ideally with aspen bedding and 1 or 2 tight hides, with temps of 78/80 and 86/88 and I would also recommend not to handle this BP until he is a consistent feeder.
As far as food an appropriate size prey equal the girth size of the animal should be offered, if fed pinky mice those are TOO small (BP are generally started on hoppers and quickly move to adult mice)
Live for now is recommended at least until he feeds for you successfully a few time.