Unhappy due to non cancellation

I called to cancel 1 of my contracts as I got it for my sister, she is now in the UK and no longer needs it, I called in to cancel it at the end of January or at the end of February 2021, I do not want to call call, wait for who knows how long only to take out my frustration on someone who doesnt deserve it. all I want is a refund that I deserve because someone between the cancellation department and billing hasnt done their job, I am tired of fighting with people who frankly dont deserve it, if I call I will get a completely different person and would be unfair to that person when/if I take my frustrations out on them, all I ask is please dont be like Telkom and say you cancelled it but cannot work out why i am still being billed for it, the number that is supposed to be cancelled is used as the ref number