Renee’s suggestion is reasonable and that is used by most programs except a few who recover the entire value of the chargeback from the affiliate. You need to check the terms and conditions which you have signed with them to clarify this issue.
If there is a chargeback, the program will have to recover a % of that from you. These are mostly case specific and discussed with the affiliate. Ask them to give you a breakdown of the chargeback.
BTW what did you spend $1700 on to get those 19 players. Are these incentive players?