Gas Recirculation Valve (egr Valve) problems of the 2015 Ford Fusion

8/15/2019 my son took my car to auto clinic of boca raton inc. =computer diagnostic scan, no charge=replaced cylinder to ignition coil-total was $90. 95(12month or 12,000miles lim. Warty. ). On 10/24/2019 my son took my car to the grayco Ford of delray beach for recalls. Engine light was back on,they wanted $to find out y the light was on. So my son left &on his next day off he took the car back to the auto clinic again. They did a diagnostic scan=free&this time=replaced cyls. 1,3&4 ignition/coils= $272. 85 this time mileage in & out was 53,473. My son mileage in for my car at grayco Ford of delray beach was 54,824 on 10/24/19. Motor was under warranty up until 60,000 miles. So I don't understand why they wouldn't of looked at that check engine light or the motor of my car for my son who was away at college in florida for 3yrs. I bought that car in order for him to go to florida and work and go to school lynn university to get his masters degree at 23 years old. I thought I bought a safe vehicle for his travels. My son got his normal oil change of every 3 months on 4/15/20@1:03pm. Engine light on after he left so he took it to the auto clinic again @2:05 they replaced spark plugs for $58. 44 mileage in 58,325 in and out. He moved home to OH the check engine light on again! I took it to classic,mentor OH they tell me my Ford engine has a problem something warps inside a chamber and lets coolant go into the motor! they want $5200 to fix it. I called Ford&it's 2000 miles out warranty. They said can�t/won't help w/ this well-known problem for 2013-2019 Fusions! I talkd to the grayco Ford of delray, very rude (david aliva) & boss very rude as well. I got a rude email,that they will not help me! even though the check engine light was on and it was under 60,000 miles! car sitting at mentor classic(since 08/20)they tell me it is a fire hazard to drive! I don't know what to do!.