Vodacom ignore cancellation of contract

I pay for a contract (includes data + handset) but theres no data reception in my area and handset is not working properly for last 5 months. Tried few times for the last month to cancel the contract but Vodacom promises everytime to do it, and everytime I follow up Vodacom says there is no record of it. Thus paying continuously for service that I dont get and Im unable to cancel the contract. In the mean time I pay for Telkom Wifi too because I cannot use Vodacom data.<br> Vodacom has already sent out technicians to my area and confirmed a lack of data services. Have also handed in my phone for repairs in January for the first time at Sandton Service Centre. Thereafter 3 times for the same fault. Every few minutes phone freezes and requires a reboot thus people cannot get hold of me. I demanded a swop out phone at the Sandton Service center a month ago because it is obvious they cannot repair it. The service centre manager said there is no record of the repairs although the staff booking in the phone confirmed that I am regularly booking in the phone for repairs. Hows it possible? Last straw. Ive also emailed customer care last week to cancel but no response. Ticket#***