MTN no regard for their customers?

I have been a customer of MTN for the past 16 years. In August 2018 a double deduction was made from my debit order account. After enquiries I was informed that MTN will change their debitorder run to the 27 th day of each month. This was done without obtaining my permission. I have an agreement with MTN for the past 6 years that my debitorder will go through on the 7th day of each month. This action is so typical of MTN not adhering to laws of countries ,and must now pay billions of rands in fines and also treating long standing top tier clients with disrespect . I have instructed Mtn to rectify their breach of contract with me or else I will cancel all contracts with them and I advise all Mtn customers to do the same!