Harassment from Credit Intel

I previously had an account with Impact Meters for my electricity, which I paid monthly. However, the property owner sold the flat, and I was given one month's notice to vacate. When opening the account, Impact required a deposit, which I expected to be settled when I moved out. After vacating, I received and paid the final invoice from Impact.

Despite this, I have been receiving monthly emails from Credit Intel, with escalating fees. I don’t understand why the fees are increasing by R100 every month for such a small amount. I refuse to pay these charges as I have no dealings with Credit Intel, nor did I apply for credit from them.

Who can I report this to?