Telkom they're ****ming people now!!

I have a Sim card deal with telkom for R449... Suddenly telkom they are deducting R650 on my account for some reasons simple because they're re saying on the last day of the month.. My debit order rejected because of insufficient amount on my account.. I'm confused why? Because I m permanently employed and I always have money in my account month end.. I called them but the lady on the call center was rude and I didn't get any help...

Like now they're still busy going to my account debitng Even thou I have paid R450

Now my account is sitting on - R285 because of a failing debit order..

I'm really confused why are they going into my account on a incorrect date because I didn't give them that permission it like they are making money toward my account now

On my contract I told them it must be last day of the month

Wandy +***