Non existent service once account paid up

On the 10th of November 2025 I accepted a settlement offer from ADRS and promptly paid. I was told that it could take seven days for payment to reflect and that it will then take another 14 to 21 days to receive a settlement letter. Despite multiple formal email follow-ups, I still have no settlement letter. These things affect my credit score / ability to get credit, but it seems that once you have paid, you are off the radar. It is sad that one has to post here to get a response.