My advise as follows
no.1
Mr.A should get a good lawyer, and if its not too late go make a police report
Mr.A should of course let Mr. B,C,D,E,F,G,etc know his intentions of sueing he/them for the the repairs and other charges too
i have seen and evaluated the damages on i think 5k is about right, but i do believe its the TOTAL COST, which some has not read this clearly, damages not only the chasis but the whole undercarriage, prehaps Ding did not mention this earlier
no.2
Mr.A should for one last resort, ask B,BB, to go to the intended workshop and settle the fees , at least they know what is being repaired,
if this fails which will eventually do, since its been so damn long to get reasonable answer from them, go ahead with no.1
no.3
go ahead and repair and make them settle the bill, if they refuse, go get a good lawyer
Mr. A is clearly being played , so please go advise him to do what must be done, or else this is gonna drag on
BTW 500 is a damn insult, its just like someone washing his hands doing something very ,very dirty.........