Side undercarriage plastic cover falling down

Look at the first picture you posted, an extreme close up, one corner of “something” plastic under the car. Give responders a break, post more overall pics, explain orientation.

 

M8ne ate all 8n trash on 2 gen3 don't miss em . Most plastics under car gone no mpg is still same no changes .

 

Just get under there with a screwdriver gun and some screws and screw it back together by putting screws through the plastic and ignore the existing fasteners and holes.... I do it all the time. Don't bother with spending money on something new that you're never gonna see. Just fix it and forget it.

 

It looks you’re on of it, with parts info. I’d score the fasteners that are missing (check, they may still be in place). If the panel holes are torn, but not too bad, fender washers may help; they have oversized OD’’s. Snipped off pieces of pipe hanger strap can work too.

 

I've got a set of four you can have might have the new fasteners too . I have to look

 

That happened to mine too. I used gaffers tape to hold it until I could get zip ties. And then when I got an oil change the mechanic had some of the fasteners so he fixed it up.