****med by mondo

I received a call from mondo offering a 20GB MTN data for R99. After few weeks i received two sim cards with 2GB each. After realizing i didn't get what was promised to me and that I was ****med I called them to cancel the contract.. they told me that they have cancelled my contract and I must destroy the sim card.. I immediately did that but to my surprise on the 31st of June R223.55 was debited from my account. I was shocked because I never used them them they told me it was cancelled and they won't deduct any money as I cancelled within 14 days of receiving the sim cards.. I decided to reverse the debit order as I didn't use their data nor their service but again on the 31st of July R433.05 was debited. I'm shocked why would they make me pay for something I didn't use. I have tried calling them, emailing them and chatting to them on the WhatsApp to this day. I haven't gotten any assistance and I can't reverse it again because it's gonna ruin my credit record please assist me