SImple plan - missed deposits

I have a SIMPLE 401(k) Plan, one active participant.  My contact reported to me that there were no deferral or matching contributions during 2017 or 2018.    My contact left the company two weeks ago.   The new contact has been reviewing files and it appears that the former contact did not fund the 401 (k) Plan.     I'm not sure where the money went, but it didn't make it to the plan.    Can this be corrected by self correcting?  or should they file through the VCP Program?   I'm not sure the best way to fix this would be.   I've never come across something like this.     

I am most familiar with 403(b) plans, but it sounds to me as though there was a failure to follow the written plan document. I believe the employer (generally) has until the end of the second  year after the operational error first occurred to make a full correction, some grace with this if substantially corrected by end of correction period...which would be the end of 2019 if errors first occurred in 2017. Otherwise, they need to use VCP. 

https://www.irs.gov/retirement-plans/self-correction-program-scp-faqs

Your problem is with DOL, not IRS. Google "Voluntary Fiduciary Correction Program (VFCP)," and within the guidance, "Delinquent Remittance of Participant Funds."