Paid up account

We bought a bed in October 2017 on credit, I decided to to settle the account in February 2018 as I lost my job. We went to sleepmasters to inquire about the settlement amount they couldn't assist us because of systems errors they were experiencing they asked us to come back the following week which we did. They gave us an amount and we settled the account as per attach. However I've recently been receiving statements via SMS that I have to pay R492.22. I do not want to go back for a third time. Please sort out your systems. I do not owe you a cent please update on your site. I would also like to receive confirmation of the paid off account.