Telkom Account issues.

I have been paying my broadband for 4 yrs directly. Telkom suddenly decided to attempt to use a closed bank account for a debit order for an amount I short paid of R13. Without my approval or any communication. Since then they have been putting through failed debit order, raising charges on those & my account has increased to thousands in these charges. This month they also increased my subscription without my agreement. Despite my paying in time every month. And despite every invoice stating bank account closed. They have ignored my emails. I will be closing my account on Monday as there are many other options available to me.