Bluebean Collections harassing me on closed accoun

After my previous complaint that I was waiting for a long time for Bluebean to close my account and refund me my money - which they eventually did - I now get phoned by them on a daily basis that I owe them more than R2000, but they cannot give me the reason why I owe them. As my account was closed and they refunded me my money that I overpaid on the account, and I do not have a current credit card, it is impossible for me to use the account and to suddenly owe them money. This will now probably reflect on my ITC record as well!