Telkom Big Deal Contracts

We bought the October Big Deal late in October which was R269 p.m. We were told that our account will only be debited in November. For October and November I paid R715.17, which I was under the impression that there might be once-off subscription or activation fees included. Telkom didn't debit our account for December which I thought it did. My December statement indicates that I owe telkom R1 185.11 and my January is R738.11.

From a monthly subscription fee of R269 to R1923.11 in total (December and January). I am well aware of the data allocation, I receive 20GB anytime data and 20GB night time data. When my data allocation has depleted I receive an SMS stating that my internet has been paused - which means I do not have data to continue browsing. And I should top up, not telkom allocating more data to me.

For December and January our telkom account has to be debited R538 and not R1923.11. If the R1923.11 is paid that sums up to R2638.28 for 4 months. So from where does all this hidden costs come from?