It's not uncommon for Facebook to tell you that verification has failed, but don't worry. The most common reasons are easy to fix, so all you'll need to do is troubleshoot any issues and try again.
Please note that you will be able to resubmit the documents for verification as long as you comply with Facebook's terms and conditions and business use policies. If this is in order, check these causes:
At least one document you sent was not accepted
The language of at least one of the documents is not one of the accepted languages
Incomplete upload or document
A document has expired
Cannot see a document properly
Problems with the company name
Problems with phone number or business address
Verification code does not arrive