Account still not canceled after 3 months!!

I have requested for my mobile account on *** to be cancelled on the 5th of May 2015 and put me on prepaid allready, I have sended the cancellation form to retainme and basically phoned the call centre about this more or less three times. I am still running on contract three months later and are they are still subtracting moneys from my bank account! This is unacceptable!!!!!! I WILL BE PUTTING UP BANNERS TROUGHOUT BLOEMFONTEIN, EXPLAINING YOUR INCOMPATANCE, IF THIS IS NOT RESOLVED WITHIN TWO WORKING DAYS!!! I OWN A SIGNAGE COMPANY!!!