We turn our DEBIT card disputes over to a third party, during my audit I have ask for the correspondence letters to the customer concering Provisional credit and the Investigation Results. Our EFT Department states they don't have these on file that the Third party does the letters and keeps them. Would this be ok, I am worried we don't have proof of compliance.

Doesn't your third party supply reporting to you that would show compliance? Wouldn't you be able to ask for copies of a sample group from the vendor as an audit test?