I have had my baby Ball Python for about 1 1/2 weeks now. It is about 1 1/2 months old. I got it from a reputed reptile specialty shop. I have it's enclosure set up just right and everything like that. Right temps on both sides, right humidity, 2 hiding places, good bedding.
Can you be more specific, I know you bought him from a "Reputable Pet Shop" and I would assume you set him up also according to their recommendation so I will ask

How big is your BP, how big is your enclosure?
What are your temps and humidity, what type of device do you use to measure them?
Can you describe your hides?

There are many reasons why a BP can refuse food however since you have a young BP the problem is likely husbandry related.