EFIN follies - need help!

Greetings,

An associate has a tremendous problem with their eFIN.   They have been in practice as a CPA for many years and in good standing all around.  In a nutshell, the IRS has currently suspended their EFIN account. It is due to no fault of the associate.  It started with a notice sent a few years ago from the IRS regarding the associate's business payroll taxes.  The notice claimed that the associate had a small balance due and the associate then sent letters in response to clarify/clear the balance.  There was correspondence back &  forth between IRS & associate over the period of at least a year (we all know it takes months to hear back from IRS).  The IRS claimed that they sent the associate demand notices (during COVID - it was NOT received)  and to make a long story short, the associate subsequently received a letter from the IRS that the eFIN account was suspended (due to not responding to the notices not received!!).  The associate has called many people to help, including their congressperson's office (who acknowledge that the IRS moves at a snail's pace in these situations).  Has anyone heard of such an issue and know of anyone at the IRS that can help? Is the only hope to hire a lawyer? I really appreciate your time!