Balls can be kinda funny when it comes to feeding, so there are a number of things to think about.

He will probably only eat when he feels secure and maybe only when no one is around. It can take weeks for a new ball to settle into his new home and start to feel secure. Whenever a ball won't feed, the first thing to do is leave it completely alone since handling them will stress them out and might make them refuse or regurgitate their meals.

You might want to try leaving the mouse in his cage right outside his hide overnight. Dangling the mouse in front of him might not be the best idea. If he can sense that people are around it may make him nervous. Do you dangle the mouse using forceps? If you're dangling by hand, you may get bit. If he smells the mouse and sees the heat and movement of your hand, it may confuse him and you could end up with a hungry ball and some teeth wrapped around your hand purely by mistake.

It's good that you're feeding pre-killed, but is that what he was getting at the pet store? Was he eating rats and not mice? Was the mouse(?) you saw him eat albino and you're trying to feed a brown one? Balls can get a certain prey item imprinted and refuse anything else without some effort.

Another consideration is the heat/humidity in his cage. Could he be in shed? If so, he may very well refuse any food.

Snakes can go a long time without eating, so don't get frustrated yet (especially since he just ate for you two weeks ago). It could be a few months before he decides to eat again and that would be perfectly healthy. I'm sure there are other reasons why he may not be eating that I'm forgetting about, but someone else will point them out.

By the way, I saw your pics in the other thread. Quite a little stud you have there :wink: Looking really good. Hope you enjoy your new snake.