Virgin Active System errors

Virgin Active has misallocated my debit order on a family plan incorrectly so that some members in my family had accounts in credit and others were owing. After taking 3 months to sort this out. the new issue is that I am being harresed to pay money even though my debit order has gone off and I have sent them proof of this. Virgin Active are saying that the one debit order that has gone off for all the other family members is being marked as unpaid on one member. They are just badgering me to pay even though it is clear that their system is faulty. Instead of addressing the errors they are more concerned with getting me to pay. The call centre accounts staff are rude and do not listen at all.