Abused by mtn

I have called mtn on the 24 March as My bill was doubled, they said I have reoccurring data , I asked the agent to stop it and she said she did her name is nondumiso, on reference ***, a month later to find out that she didn’t stop that option as she advised, cause April again I was billed the same amount, was helped by sizakele on reference ***, which I asked if she can cancel my contract as it’s over 24 months and can’t handle the abuse from mtn anymore. She said on her side she can’t but will put me through retentions which she did and I was on hold for 2 hours with help I eventually cut the call, I sent an email and I got a reference number from *** From Nandi that my request has been sent to retentions, I must wait 48 hours with no response again I sent another email Thabo mashigo replies again with the same automated email with the reference ***, that was on the 28 April and I asked them nicely to cancel the contract to avoid being credited of their data that I don’t need and will be billed for in May, but that was not done given enough time to do so, today the 12 May I’m credited with data on the same number I asked they cancel, what more should one do? I should pay R2088 again for services I don’t need from mtn? I decided to cancel the debit order payment option and did an eft transfer funny enough that one they sent an sms and acknowledged it, but leaving their abusive network they don’t do it. Iam honestly tired with mtn & don’t need their services anymore. I sent a DM on their twitter page same response aswell that it’s sent to retentions. Can they cancel my contract that is over 24 months. I do not need their services nor will I pay this month the credited data as I asked it be stopped way long before .