Disconnecting My Line for No Reason After Even Paying a Month's Fee Up Front

Every month, MTN disconnects my line although I sent them e-mails with proof-of-payment, and even after I paid them one month up-front to ensure that this doesn't happen. Sure as hell, they still disconnect my line.

I sent them several e-mails, asking them to kindly confirm receipt thereof and to get back to me. However, after months of sending e-mails, they don't even bother to contact you. Seems like it is not important to them at all.

Yesterday (01 February 2022) they disconnected my line again. I phoned, as usual, and after speaking to the third agent, they finally reconnected my line. However, a few hours later they sure as hell disconnected my line again.

The absurdity of trying to make the proverbial penny drop becomes clear.