Querying the debt could be construed as an admission of part of the debt but then so could the paperwork Mortgage Corporation/First Active hold so it's a non-issue.(posted 8263 days ago)With regard to your question: "what to do next?" Read the material at this link and prepare whatever you can: http://www.home- repo.org/dos/statdemand.htm
Then you need to read pretty much the rest of the site to get your counter attack going.
I see the Do's and Don'ts link in the Repossession section is broken at the moment but I will fix this shortly.
Lee