MTN is up to no good!!!!

I've been trying to cancel a MTN cell phone contract that has expired November 2020 now for more than 2 months with no success. I've send numerous unanswered emails and made a ton of phone calls to that 135 number. each and every time I must here they're experiencing high call volumes and if I do get through to customer care they just tell me they have few staff at the cancelations dept. due to Covid 19. how long do I have to pay for MTN`s inability to deliver a service? can someone please assist....