I want pay up letters

I took a loan with them the amount of 8000 which I have to pay 4 months..which I was paying 2200 the last payment u defaulted and the information call them for banking details so can deposit the money. They gave me a topup loan of 500 againg while I was still owing themy the 2200. I stranfer 3200 on thier account and 700 buy differnt dates. My issue here is they told me I haven't paid this two accounts and they have already hand over me to thier laywers...the lawyers calls me telling me that am owing Atlas...I send proof of payment to thier lawyers and tell them that I have paid that account long time is supposed to be closed by now...they were amazed when they see proof of payment done 2018 and I haven't got the paidup letter to them. It amazed me when I check my credit profile still am owing them. I send them email last week ..they said they will come back to me ..till now and is 2021 is four years back. Please they must just remove me on credit score that am owing them and give me my pay up letter.