Yes, you can be sued by a third party collection aganecy for a claimed unpaid debt even though it may not have backup documentation for the obligation that you supposedly owe nor have in hand your file that you have written about.If that happens to be the situation that you are being confronted with, the absence of documentation supporting the third party collection agency's claims against you would seem to be a huge hurdle that it will need to overcome if suit is actually filed and you go to trial.