Well I can give you one scenario....Mine!
Of course our case was not the norm.

Our house was foreclosed on in May of 2000. But, it was due to the arrogance, the fraud and the incompetence of the companies involved. Our first mortgage company kept saying we owed two payments and would not accept any other payments, even though we kept asking for proof of the two owed payments. At the time it only should have been one payment, and that was because they had LOST a payment! One which we tried to get them to tell us something about. (we were sending each and every payment by certified mail due to earlier problems with them, so we know that they had gotten it).
However, after wrangling with them for two months, before we could get a lawyer involved, they sold the mortgage to another mortgage company, one out of state mind you.
Well we then proceeded to go through everything all again with them. They too wouldn't accept any of our payments saying we had to get the other payments current! We kept telling them, the only problem was with the lost payment and that it was only one payment. However, they too absolutely refused to audit the account, tell us what was going on, etc....
And, even after getting notice from the lawyer we were then using, they refused to do anything and foreclosed on us.
Moving on to a few years later, they both lost in court. The first company had been hiding a payment (one which they had received years earlier, but had misapplied, but still wanted to collect, even after the lawyer we used then told them they could not), and the second payment, the one they lost was actually paid from monies in escrow. We never were behind any payments! And, they were caught falsifying records in court. Our lawyer (different guy than the first two), burned their rumps! Using their own papers, no less.

The second company also lost because they had refused to honor the contract, which meant they refused to do their job.
Well we just got the payments last week from all of this. Six years later!
However, we never thought of selling our home to take care of this 'supposed' debt. We knew we were in the right and our case was based on a proper audit being done on the account, which never happened.
As for the first payment they were asking for, it was a payment that had been made before we filed chapter 13 in 1994 because of our daughter's extreme medical bills (we could not get any financial help the first few years). And our bankruptcy lawyer told them that they could not collect on it, they should have said something in bankruptcy court originally. And, they then hid the payment, since they knew I had a 'bad' habit of keeping good records

, and they figured that they would ask for it when we came out from under the protection of the federal court. Which they did. They started trying to collect on it the very month after we paid out our bankruptcy!
And, that is one reason why people don't sell their house......

I know....Pop Daddy, long long post.
Kim