Oh my gosh....first thing...relax!!!

Your ball is 820 grams, that means he is at breeding size...it's breeding season! I have ALL my adult males off feed at the moment. All of them! They do this, it's normal, and getting pissed every time he refuses is going to drive you mad.

Just try offering every 2 weeks as to not waste mice/rats, if he takes it, GREAT. If not? Then try again next time. As long as he's not losing a crazy amount of weight, it's normal, and should be expected this time of year!

Take a deep breath lol.