Ours was the same way we had to have puroclean come out and do it, they used disinfectants to make sure no mold spores grew. They cleaned every single thing that was in the basement by hand with a special cleaner. They also removed about 5 inches of the drywall clear around the basement. They brought in huge heppa filters and left them in for 3 days to get rid of any odor. Total cost was like $4000 and home owner's insurance would not pick up the bill.