How it possible Chase reverse a foreclosure from 3 years ago?
The have sent paperwork for an escrow and helpful paperwork to get help with catching up payments. But the best is sending a letting that they were going to reverse and they would let the credit bureau of the change.
Don't know what to do other than really wanting to sue the crap out of them for harassment.

They probably can. But why would they want to?

Perhaps in a review or audit or foreclosure practice, They found an error in the foreclosure. Perhaps they did not have the foreclosure properly reviewed, perhaps some documents were missing.

So if there was a procedure error, they have no choice but to reverse it,