Depends on where the issue exists, and if it is one that manifested immediately (in which case, just restore the last known good backup or the transaction logs until that point. If the error is more systemic that had been around for a while, it might take longer to locate. Also depends on if they are willing to give up all data past a certain point, or they are attempting to locate the individual record that is causing the corruption...latter would take significantly longer.
Granted I agree that it is odd it is taking them this long...just trying to think of a technical reason it might be occurring, but I am starting to wonder myself actually.