Account query not resolved

I had a loan with Finchoice which I struggled to pay. In September 2015 I was contacted by their legal department/ debt collection company regarding this loan and I made an arrangement to pay a R300 monthly, which I did. In July 2016 I contacted the company for the settlement amount and I was given an amount of R3100 as full and final settlement which I paid in full on the 11 July 2016. To my surprise on the 10 April 2018 (almost two years later) I still received a sms from DMC debt collectors that I still owe Finchoice some money. I have since been struggling to get Finchoice to resolve this query. I was reffered to their legal department which the lady(forgot her name) that I spoke to promised to come back to me and never did. Please, someone from Finchoice follow up on this matter and check on your systems for the first company you sent my account into as I have paid the account in full. Pity that I do not have their details anymore. Kindly give me the contact details of the first company you assigned my account into, as I would also like to contact them.