Incorrect billing for over two months

Telkom billed me incorrectly twice and when I call regarding this matter I'm told the case has been locked in and they will call me within 72 hours its over two weeks now waiting on they call. When ever I call they help line they sing the same song I'll email them to call you. Why is it that Telkom debit us every month with no hustle but it's a drag to credit us back,do we take this money from trees I'm sorry but I'm just annoyed about this matter and think it's best I take this matter to my lawyers. I will not tolerate this behavior cause I believe I'm a loyal customer not for once have you had a problem with my payments but today it's a drag when I have to be credited back.