Very bad service

Early 2014 I purchased a cell phone from Markham at Carnival Mall and was offered an insurance for it (which I accepted). Shortly after that I decided to cancel the insurance (before August 2014). I went to the same store at Carnival mall to have this done. I was assisted by Nokuthula who asked me to complete a cancelation form which she advised that she will send it to their Head Office. In December 2014 I decided to settle the outstanding balance on my Markham account and the only thing I expected to pay from then on was R28.00 for the Legal Protection plan but to my surprise, when I got my statement in Jan 2015 it had a balance of +-R94.00 instead of R28.00. I then decided not to pay in Jan 2015 as I realised that I was still being charged for the cell phone insurance that I cancelled in over 6 months ago. On 14 Feb 2015 I went to the same store to query this matter and was assisted by Lebo who advised that she will ask the lady (Nokuthula) who deals with cell phone insurance to assist but Nokuthula could not help me. On 21 Feb 2015 I received a call from Archie ***) asking me to pay my account as I now owe +-R240 and even after I told him my problem he didn't care...