CELL C BULLIES OVERBILLED ME THEN BLOCKED ME FROM COMPLAINING

I have been over billed for the month of November 2020, this is according to their statement. I raised this, they are refusing to refund my money claiming that they sent me a statement for December however upon request for the November one they are unable to send it, the keep sending statements for other months (which I did not request) excluding the month I am quiring. Their social media team excels with rudeness, so I was equally rude as I am raising a legitimate complaint which they refuse to resolve. They even blocked me on their social media because they know they overbilled me and don't want to refund my money.