Telkom debit order sucks

<p>Took a router contract with telkom TygerValley shopping center 5g day 10gig night surfer and pay R149pm. In march they attempted to deduct R798 because I only had R500(R149 for Feb and R149 for March) to me R500 is enough for that thier debit order bounced went to the store to check what happened was told I exceeded my limit. I asked them to only give 5gig day 10gig night nothing more.but this month April R1650 was deducted from my account but why????? Because I expected R798+R149=R947whyyyyy R1650????????</p>