handed over for Cancelled contract

I have since cancelled a contract with the gym sometime in March 2013 and today i recieved this sms:<br> Ms SHIBAMBO your overdue Body Lab acc with balance of R12698.96 has been handed over to Ver-Tex Solutions.Call *** and quote BLG-***.<br> <br> I no longer have the proof of cancelation since there seemed to b no complications for over 2yrs. <br> It was a joint contract between my n my friend since it was cheaper when u bring a partner but to make matters worse im the only one getting black listed.