Incorrect amount debited for the second time!

I was previously debited incorrectly by MTN in December, which took a while to sort out and eventually a credit was passed on my account but then I was incorrectly debited again last month. My debit orders are set for the first and when I noticed the amount was a lot higher I immediately emailed customer care on the 2 March and to date I have not received a response, I have also sent a second email and tried explaining my issue to an agent via Messenger who does not understand my problem and keeps giving me excuses and information I already know, I need to know why an incorrect amount was debited from my account for a second time and when you will be rectifying this! Also please can you train your agents to directly forward customers information to the relevant departments if they are unsure how to assist, instead of beating around the bush and making your customers even more frustrated!