These two letters are simply warning letters to alert you to a POSSIBLE problem with the returns you are filing. I would suggest you start to gather more documentation for any EITC return you do. Get copies of birth certificates. Get a copy of a school record. CAREFULLY READ the Instructions and make sure you are in compliance. We did have one user a couple of years ago that was hit with something like $50,000 in penalties. They never came back to post a resolution, but I do see they are still in business. 

IRS operates a honesty system based on FEAR. 

https://www.irs.gov/pub/irs-pdf/i8863.pdf