Unable to cancel month to month contract

I am struggling to migrate my month to month contract to a pay as you go. I contacted the call center 4 times and everytime after trying to convince me to upgrade they put me through to the retentions department where nobody answers. I visited the Canal Walk store where they said I can only do it via the retentions department. I emailed *** on 26 July and received a response for more detail on the 29th July ( *** ) on which I rep**** 1st of August. It's now 1 Sep and I haven't heard from MTN since then.