Preferred Mortgages

We have been with Preferred Mortgages for a little over 2 years now and sine then we have had numerous letters stateing that Capstone will now be handling the account. (Even though Preferred Mortgages have not gone into liquidation as the impression has been given).
I am really concerned about a letter that we received asking us to settle our mortgage early and if we did this in the next 6 month they would give us a discount of 12k off our mortgage, with no redemption penalty which is about 4k and 2k cash. When we phoned to ask them why as we think you dont get something for nothing they said that they are not a "regular mortgage company" They have investors that put money into the company and all it is is that the investor wants their money back before the term of our mortgage. I was wondering if anyone had ever heard of this? I am worried in case they have already misssold the mortgage and trying to offer us a deal that seems good but in the long run isn't. Our Home is 50% shared ownership so we only own half of our house