Contract cancelation

Good day. From the beginning of December 2025 I have been trying to upgrade my contract. At mall @ carnival the lady have told that something is wrong with her system. This appears to be the story at MTN wherever I go. I have tried online to upgrade as well 6 times if not more and still nobody could help me. After that I wanted to cancel my contract and still have the same problem with MTN always having the excuse that their system is slow. I still want to cancel my contract but nobody wants to help me. I have never seen such bad service in my life !