Unhappy with the service

I am expressing my feelings with DMC as extremely unhappy client with their service. I have two accounts with them as collectors for Joshua Doore. On the 7th of December 2023 I opened my DMC online chat and communicated with one of their agent, and asked for settlements discount then I was given figures of how the payment will be. On the very same day I asked settlement quotations in order for me do payments with references. I did quoting the details as per their letters indication , Now the challenge is that my first payment was not received but the second one was received successfully. When I try to find out and chat with DMC agent they keep on telling me that the matter has been place to query’s department and I provided proof of payments. How come they receive the second account payment not both, when I checked my DMC accounts it shows the outstanding balance. And Debit order for this account will still deduct.