Large welfare plan paid DFVCP payment but never submitted filings

Large welfare plan client submitted DFVCP payment in 2020 but has never submitted a filing (we do not have a service preparation contract with this client). The group likely crossed 100 participant threshold in 2013 or 2014, but not 100% sure without doing more research. What is their best course of action in this situation? Should they reach out to an ERISA attorney to assist?

Thank you in advance! 

Yes