Settled Account is still active & interest charged

Good day, I had an account with RCS Group which I settled and requested the account to be closed once settlement has been reached, however this was back in 2010. This morning I received an email from Norton Lambrianos Attorneys stating that I owe R307.00 and they are collecting the payment on behalf of RCS Group??? I never received any communication whatsoever and now I find out that I still owe RCS Group? No effort whatsoever was made to contact me from RCS Group to inform me of this amount outstanding and I refuse to pay this account as I did request it to be closed once I had paid it up. Kind regards<br> Jody Simons