Well, yes if it was withdrawn from your credit card account.
Yes, that's what I did in last month (July) and I wasn't penalised.
Side note: If one is capped on say Checkers or Fuel spend in terms of the 20% rule, it may still be advantageous to buy prepaid on credit card account. The money you get back in eBucks (if capped on Checkers or Fuel spend**) outweighs the interest that FNB will charge you. I can elaborate but it's getting late :/
**You won't know this until the end of the month or unless you are really good at forecasting your monthly spend.
No, not if withdrawn from your cheque account.
OK, but do you have a bond? For example, if you put 10k into your bond instead of keeping it in your credit card account, you save R80 interest per month, R950 p.a. (based on prime, 9.5%) Ideally this would be an access bond in case you need that 10k.