MTN won’t let me go after end of contract

My 2 yr contract ended 11Nov and I notified MTN the requisite 30 days ahead on 11 Oct. At no time during that period did they ask what I wanted to do after 11 Nov. Without my permission they put me on a month to month contract. Meanwhile I have entered into a contract with another cellphone company but we have been unable to port my phone number for well over a month now which means since a month I do not get SMS’s and cannot get any calls. All MTN does is send me complaint reference numbers.