Telkom Dom Dooste

Why did Telkom decide that they want to debit my account earlier in December without consulting me? My bank account was empty at that time because I only get paid end of the month, then the money would've been ready for them to debit like always. Now I have a no funds available fee of R25 at Standard Bank and I also have to pay a R202.70 Payment Rejection fee to this dooste who call themselves Telkom. And they told me I can pay them manually before the 31st of December, and I did. I can't hardly wait for my contract to end. I'm gonna give them hell!