Provided an applicant with a adverse action on incomplete application and provided 20 days to provide. No response received is the action taken the date when the adverse action was done or the deadline date to provide information?

If you sent an AAN use the date of the notice. If you sent a Notice of Incompleteness use the date you closed the file for incompleteness.

You don't need both. If you sent an appropriately worded Notice of Incompleteness, the bank does not need to send an adverse action, and like Dan mentioned use the date you closed the file for incompleteness - 20 days after you sent it.

Actually, can't you use either the date on the notice of incompleteness or the date you closed the file because the date to respond in the letter has expired??

The key is consistency.

GIR: " For applications (including preapproval requests) that did not result in an origination, enter the date when the final action was taken (e.g., the application was denied or the file was closed for incompleteness) or when the notice of the action was sent to the applicant."