No service

My contract expired 24/01/2015 so I mailed the MTN support to give them a month notice. MTN rep**** and said if I want to terminate my contract I have to give notice but in my case where I want to move over to prepaid, I just have to phone after the expiry date of contract. I phoned call center 3 times as they keep on cutting the line and after holding 30 minutes still no one helped me. I then send a mail again to cancel my contract with no reply, after sending another mail I received a reply which said my query will be dealt with. Still this is not sorted and they deducted the money from me. Needless to say I am still waiting for any feedback and find this unacceptable. This is for my tablet and not a cell phone