You have Sections1692 (FDCPA) and Section 2605 (Servicing of mortgage loans and administration of escrow accounts) confused with one another. Section 2605 is where a QWR comes into effect. They have 20 calendar days to acknowledge receipt of your QWR and 60 calendar days to make a response. I do not believe 1692 says much about timing other then you must dispute the claim within 30 days.
Here is the link to Section 2605:
Hope this helps