It seems you are experiencing issues with the employment verification process in the Microsoft Partner Center, specifically related to document submissions and being blocked from sending new documents due to exceeding the allowed attempts.
Unfortunately, the context provided does not contain specific guidance on how to resolve issues related to exceeding document submission attempts or unlocking the ability to submit new documents. I recommend checking the official Microsoft Partner Center documentation or reaching out to their support for assistance with your specific situation regarding employment verification and document submissions.
References: