Bad service

I was contacted by a call centre agent who called to confirm on which date will i be paying my account which is always paid after the 26. In January i paid via EFT and i never received any notification that the payment was received and allocated to my account number. I sent an email after receiving a second call for the same reason. In the email i asked if they received my payment and on which date it was received? I also asked to them to stop calling me and sending me sms's may the contact me via email only and i want to cancel my subscription to receiving a magazine. Tanya responded and confirmed that she has cancelled everything. I received a call again from a call centre agent who called for the same reason, i asked the lady if its not noted on their DRM that i asked not to be called she confirmed no. I am the one who is liable for all these stupid calls which are billed at R20 per call and sms at R20 too. Now how am i supposed to pay for all these 3 calls when i asked already last month not be called or to be sent an sms?<br> Sportscene kindly inform me on what am i supposed to do to get the message across that i do not want a phone call or sms from you?