Contract cancellation

I have been trying to make an early cancellation of a MTN data contract since 26 October 2021. Apparently one can only make a cancellation by calling 135. It has taken at least 15 attempts. Every time that I have been told to hold for the "Retensions? Dept" I land up listening to tunes for 5-10mins and never get through.

This afternoon, 10 November I eventually got through to the Retensions? Dept. I was told to call 135 again after paying R104.00 at an MTM store.

Apparently only Retensions? Dept can process a cancellation. This is ridiculous. Why can't a MTM store process a cancellation? They process contracts at the outset.