I just want to know if auditors did their job properly or...

I just want to know if auditors did their job properly or current procedures are really sufficient to sign off on financials. Seems to me that there is a miss here. How could a company write off inventories few months after audit sign off. I would think that some of these should have been captured during the audit particularly slow moving items that an auditor can say "hang on what is happening here?". Sometimes auditors have to go to grass root level of the company more rather than just looking at spreadsheets and relying on management.