poor customer service

i had four contract with mtn and called their customer service more than once to try and cancel three of my contracts that had expired and everytime their consultants gave me a different date to call. I was told i needed to return the router of which i did at their store in Rustenburg Boitekong mall, however my contract was still not cancelled nor did they acetoin my request to cancel only after i went to enquire i found out that the cancellation was not actioned. Today i find out again that i am expected to pay to R2700 for contracts i cancelled in December. If there was a zero start i would definitely rate them 0