Very disgruntled customer

I paid up whatever outstanding amount I had with Mobicred on 18 June 2025 and I sent them an email requesting for my account to be closed immediately. However, I haven't heard from them since and now I see that I aparently have to pay them R92 this month for an account that I have only used once. I sent them another email yesterday requesting for my account with them to be closed and they still haven't got back to me. They are very unfair and I refuse to pay any amounts after specifically stating in writing that I want the account closed promptly. I am very unhappy with how they have not handled my matter to date.