Virgin active membershipped was blocked, how do I owe a blocked service

Im disappointed. I signed a contract at virgin active. I only gymed for a month after which I told thEm im retrenched from my job. They blocked my membership, which means I no longer gymed but they handed me over and I now owe and im at a rism of being black listed. Please assist because I only gymed 1 month after which I became retrenched. I refuse to pay the R2000 that Im told I owe. This is fristrating