contract not cancelled

My contract expired on 28/11/2015. I went to above mentioned branch on 30/11/2015 to cancel and as to date the contact has not been cancelled. i phoned on 02/12/2015 and spoke to Melanie again who assured me that she would put in request again to cancel. attempts to phone the customer service line has been unsuccessful as well , you hold on for ages and then they request a pin. on 05 dec we did get thru to a consultant who advised that it would take 30 days to cancel which i find absolutely ludicrous. i went back to mtn store on 5 dec again but Melanie was out on a break and i left my details for her to contact me. to date i have not received a call or any feedback at all. customer service is bad waste of time , spending endless time of phone and then also going into store to solve my problem. contract still not cancelled.