Just relax first of all. Especially if it is overweight. Snakes can go a long time without food and a Ball refusing food is not uncommon. Mine has done it a few times, 3-4 months at times. The only down side is wasting food but with the others in my collection they take care of any refused items for me. Good reason to buy a garbage disposal of a snake to have handy. Lol!
When I do have a refusal I stick to my schedule and do not offer again until the next time to feed my collection.