Double Charging Me

It’s almost end of month and cell c hasn’t rectified of gotten back to me about my billing complaint. They are double charging me end of this month and when speaking to agents they even fail to explain the reason why cause what they are telling is wrong but when I ask them questions they don’t have tangible answers. I logged the complaint via email due to not having time to speak on the phone in which I require an email response but they keep calling me even though they can see I’m not available, they are not even leaving messages or sending emails and no longer replying to mine. I am so disappointed as I’ve never experienced this with them and really annoyed cause this is my money and can’t even stop the payment cause it will mess up my credit🚮 they need to sort this out!