Keep getting form CP214 even though S corp was terminated. Worried about $150k penalty and /or $1500

I keep getting the CP214 form sent to me to remind me to determine if i need to file form 5500-EZ. I ignore it because it said we send this form just to remind you if you previously filed a form which I did in 2014. So today I was curious and I called the IRS. I said why do I keep getting this form even though I terminated the solo 401k plan.

She immediately ask me if I had the 5500-ez in front of me. I did and everything was filled correctly EXCEPT the part that said "total number of participants at the end of the plan year". I wrote 1. She said I should have written 0 and that is why I keep getting this form. The Assets was already 0 and I wrote Final written. I was told to mail a amendment for 2014. I asked if I have to pay a penalty. I already converted the plan to a traditional IRA in 2014 and already issue 1099 and my asset at end of year was 0. He said I should not. He claims I don't have to pay a penalty because I filed it on-time but I just filed it incorrectly. I was told to mail the letter with an explanation and a 5500-EZ. Is the IRS agent correct? Anyone ever encounter this? I read online somewhere I need to pay $1500 penalty or $150,000. I was the only person on this solo 401k plan and I only file this return (due to final year) once because my plan never exceeded $250k nor was it even close. 

Do what he said. For whatever year you filed with "final" indicated, amend it to show zero participants at the end of the year.  Do not lose sleep.