Woolworths won't close my account

I have owed woolworths for some time due to unemployment but making minimal payments. Yesterday I went to woolworths and required how much I owe and paid the full outstanding balance.

I went to customer service to close the account and wiolworths tells me they can't close the account because it was handed over to MBD. I have never had a call from MBD.

Phoning MBD I was told the amount I paid is incorrect. They say I have to pay R520 which is their fees.

This is the worse thing I have ever heard. I wasn't paying my account because I don't work and made an effort the settle the account to be told I need to pay MBD a fee for services they have rendered to me .

What does NCR say about these type of issues?