Trying to get a basic request handled at MTN - not possible

Trying to place a notice on my contract not to renew. MTN has the worst customer service with regards to trying to put notice on a cell phone number that you wish to cancel. i am currently living in Santiago Chile and have two MTN cell phone numbers. My one number expires on the 27th of June 2021, so prior to leaving South Africa I requested that when my contract comes up for renewal that they place a notice on my acccount that the contract does not renew, but will be cancelled. I was advised that this was not possible and that I must call closer to the time. When in Chile I called about six weeks before only to go through a long procedure to be told that I must call closer to the end of the contract. I thought that due to the fact that contract ends on the 27th June I would call on the 8th, same long wait going from agent to then retentions again, only to be told cannot place the notice on their system, I need to call on the date of expiry to cancel. I cannot believe that the system does not allow me to give notice of my intent to cancel a contract that expires about three weeks time. The date that my contract expires is a Sunday during which there is no MTN customer support. The whole system at MTN is pathetic, when I eventually get back to RSA, I will cancel my other MTN contract as well and go with another provider