Mtn not following protocols to black list customer

I am so disappointed pointed with how mtn is handling their contract customers. I took a phone on contract and they never deducted money I went to the store to enquire about this the lady that was helping me said she didn’t send through my account details I signed again then they deducted and stopped again I went to the store to ask they said they will fix it up to today they have never resolved the issue only to find out this is affecting my career when applying for jobs they tell me mtn is showing but I have never received a call nor an email from them nothing, I regret opening an account with them