virgin active failed to cancel membership

Upon calling virgin active to request cancellation of all family memberships I was promptly told that they would auto cancel with the cancellation of vitality. My wife went into a branch and they confirmed the same. 3 months later I've found they were still debiting for my child and wife's memberships. Upon calling I've been told they have no record of my call and, as such, will keep said money. Their incompetence just cost me thousands of rands.