I rent a house, the house is in foreclosure
The owner has not cashed the last 3 rent checks
Therfore I haved no proof of payment
Should I contact the foreclosure laywer from the bank holding the note?

Contact the lawyer and see what s/he advises. You may want to stop payment on those checks, as the owner could cash them after the foreclosure is finalized... but see what the lawyer says first.