Terrible service

I have an account with a company called JD finance. I made a purchase and took my stuff on credit. I paid 5000.00 in advance. The monies covers my installments until October 2021,however I am continously harassed by this company stating I have not made payment. According to my knowledge I had a balance of on 800.00 which was 2 installments. The current balance is now 2600.00. This company is *********, unprofessional and makes money out of their consumers. I have continously explained myself to their consultants that call, however nothing seems to be done. Very unsatisfied with pathetic services