Contract Cancelation

I canceled the contract for router due ro my dissatisfaction about the data that will finish within a week. How can we finish 100gb within a week. My kids are all schooling and I'm always at work but within a week you will get an sms stating that you are on reduced internet connection because your data is finished. I posted on Facebook under a comment of another customer complaining about the same issue that I was experiencing. They immediately inboxed me and I told them I want to cancel. They advised me to take the router back to any MTN store 3 to 5 days before the debit order date.I did exactly that but to my surprise the debit order went through for something I don't have.I went to my bank to do a reversal and only to find that they blocked the access to reverse my money and they even blocked the bank to have access to block them to debit my account. Which is a clear sign that they are ****mers.I am being taken from pillar to post to cancel their ****** contract. I hate Mtn ! Im left with no choice but to change the bank because of this ****mers