Everything in the above post sounded like great ideas to me, but I did want to add one other thing. Granted ive only been feeding my little girl, so im not sure if this is her own little quirk or not. She acted very much like the way your ball is acting for the first three months we had her. We were attempting F/T in a feeding box, but she just acted scared of it and spent the entire time trying to escape her box either running away from or ignoring the mouse. Eventually we tried an act of desperation and set her on the basement floor(Which is carpeted) after making a circle with a blanket so she wouldnt run off and get lost and she took the mouse immediately. Like I said im not sure if it would work for yours or anyone elses, but its the only place my little pakul will feed XD. (I dont feed in the hide because I heard that they will associate your hand entering the enclosure as dinner time, and strike at you unintentionally)
One other thing ive heard from a friend of mine with a ball python. He also feeds frozen thawed and found that his snake wasnt taking the mouse because he was holding it too high. The snake only went for the mouse if it with within an inch from the snakes ground level.
Good luck! I hope he/she decides to eat soon. I know the frustration and worry of having them not eat for you and its awful![]()