Closed Account being Charged

I got a SMS that my account has been handed over to Brooks & Luyt Inc , shortly thereafter I got a SMS that an external service provider will contact me to discuss payment arrangements to settle my personal loan. I don't have a Standardbank account anymore and this was closed +/- 4 years ago and my personal loan was settled +/- 6 years ago. I phoned *** and I was told my account is closed but there is an outstanding amount ? .. I need to know what is going on here and why did it take 4 years to tell me this, Why this inconvenience ?? How do I sort this out, I don't have time for this nor will I go into a branch to sort this out as this account is closed !!