Most common way this happens is that the person that is in foreclosure waits until the day before and files for bankruptcy (usually a chapter 13). That stops the foreclosure.

They client then normally doesn’t show up to the creditors meeting and the bankrupcy is dismissed and the bank must foreclose again. Eventually the court will rule that they cant file it again. Ive seen it go up to 4 times. Which took about a year to get them out of the house. Looking at the above comment if 2 were on it. Wow that could take along time if they were doing that. They just keep filing the day before until the judge dismisses it with prejudice. And then the other person could start doing the same.

Call the bankruptcy court and see if they have been filling for bankruptcy or call the court and ask why the sale was cancelled.

most likely they filed chapter 13.If both spouses are on the loan they can each file at seperate times.After this they are most likely out of luck.