Cancelation

Mtn has become a problem that does want to solve any of my queries, I called early March no help instead they cut my calls. I was advised to write an email to retentions mailbox on the 26 March 2021 and 27 April 2021 I sent them an email till now there is no response. All I want is to cancel my data contract sim. On top of that I get an extra 49 being deducted of my account.