Telkom debit takes more than a week to reflect

So... I paid my account at a Pick and Pay and then the following day I was debited the same amount. It is a week later and the debit is still not reflecting. I want to reverse this transaction as Telkom has now received double what I owe. Over R3000... How does it take more than 1 Week for a debit to reflect?! I have mailed and called serveral times this wee****