2004 Lincoln LS review from North America

I've been posting on auto sites attempting to find out if other Lincoln LS owners have had problems with the seat backs. Both seat backs fell down the same week. The Lincoln dealer where I leased the car has gone out of business and I was redirected to a Ford dealership. They refused warranty coverage on this 2004 with 18,000 miles as they claim the seat backs must have been improperly removed during an earlier repair by the dealer who went out of business. Customer service at the 800 Lincoln number supported their refusal. Neither are willing to consider it might be a part defect. I have seen a few postings that relate problems with the seat backs on earlier models of the LS. I'm attempting to discover how common the problem is. Thank you.