Telkom's debit order rejection penalty unfair?

I've been with telkom since 2018 and never had a rejected debit order till now when my money was deposited into my account a few hours late. I thought,ok, they'll pick up the payment when they do a 2nd run, but no, they slapped me with a penalty of R202.70. Is this even legal, i mean the bank only charged R10. Apparently i signed a penalty clause in my contract, which i have made 2 attempts to acquire only to be met with obstruction. I ask for an e-mail response and a ref number so that i can take it to CPA or ICASA. Nothing. Surely this falls under unfair business practice? Has anyone successfully taken this issue further? It's a money spinner for them. If i was a delinquent payer, i could understand it. Long term this policy will backfire as clients will choose elsewhere. Anyhow ,a penalty clause doesn't supercede the Consumer Protection Act