All examinations are risk based so if they feel your internal audit department does a god job monitoring, then it would be a wait of their time to question the IA's work. They are concerned with the areas that you are either weak in or are not fully aware of.
If you feel cheated, call them and tell them all of your problems and request that they document your dirty laundry in their examination report. After you do this, get an empty box and fill it with your desk contents and await HR. They will have your pink slip within a few minutes of the exit meeting!!!
The opinion stated here is what it is, My Opinion.