Yep. My better half used to withdraw cash from her CC to pay some stuff. She also did EFTs from the CC in the past. I put a stop to all of that. She was unaware that they hit her with interest from day one. Standard bank hit her with her last 'Cash withdrawal interest' this month - a whopping R0.01.
Unfortunately I had to implement a similar strategy for her with regards to 'rolling' her debit. I push through 'payments' on the card to lessen the interest hit she it taking on the debt. She eg. owes R4000. During the month we eg. pay in R3500 or whatnot. That R3500 gets used again, sure, but the interest only gets charged on the 'outstanding' R500 and not the full R4000 if we were to have used the R3500 cash directly and not via the CC. This is not optimal, I know, but it is how things need to be for now.