Abused , bul**** and treated unfairly

If there is one thing that I regret doing is taking a cellphone contract with MTN. What I have signed on the contract vs what they debit every month are two different things. Even after querying and them promising to pass credit has never happened to date. I am basically being de*****ed, being treated unfairly not to even mention the long hold on the call centre without any help at the end of the call. This has been happening since last year. To top it off- MTN forgot to debit my account in November 2023 and closed the SIM card from working . December they tried double debiting me a double amount of which it bounced bcz they forgot to debit the previous month. In January 2024 they debited for three months an amount of which I did not agree to as per the contract . I have given them ample time to resolve the issue as MTN but with no luck . I wish to cancel the iPhone cell phone contract with MTN. I’ve never been abused by a network provider