2017 FORD F-450 Unknown Or Other Problems

tailgate opens while driving could cause jackknife of trailer and truck has recall, recall has been performed 3 times and still having issues midway ford inspected and said the tailgate is functioning as intended no warning or indicators this is 2nd time this has happened and recalls have been performed also have surveillance video of me leaving a customer's house with tailgate up and closed and when i pull to end of driveway and make a left u can see the tailgate come down while in motion driving .ford motor company and the dealer refuse to help with damages and have no concern this could happen to me on a off ramp or at higher speeds and this could end up in a life threating situation, they cannot offer me a fix or repairs to my vehicle or trailer even though i have a letter from them that says they...