with his team and didn't want to go to practices and even some of the games. I sat him down and told him he had committed to play for the team and he needed to ride it out and if he absolutely wasn't willing to, he had to go talk to his coach to explain he wouldn't be playing anymore and he would reimburse me for the amount I paid for the season.

Same goes with piano. My son wanted to sign up and was not forced. If and when he wants to stop practicing and quit, then he needs to tell his teacher. I won't make him pay anything unless I have incurred any costs. He is also aware that he is expected to practice at home and if my wife or I notice that he is not practicing and the lessons are fruitless because of his lack of effort, then we will have to figure some sort of consequence which may include reimbursement for lessons that were pointless.