I didn't read all of the posts, so sorry if this is repetitive.
I had a emergency brake backing pad (or something like that) go bad on my Tundra. I have an extended warranty on the truck and about 45,000 miles. Took it to dealer, they called Toyota, warranty denied. I called Toyota... warranty denied. They said its part of the braking system and is a wear and tear item. Its definitely not, but figured I was screwed on a technicality. I am a member of a Tundra forum and sought out advise there. Some users with similar problems had mixed success.
Finally a poster encouraged me to contact Toyota and not allow the warranty claim to be denied. He provided me literature from Toyota that cleared identified the brake backing plate as COVERED UNDER THE WARRANTY. I called Toyota and got the same response. I told the guy that his answer wasn't satisfactory and I needed to speak to a supervisor. Spoke to him, he tried to deny it. I faxed him a copy of his own literature that clearly identifies it as COVERED. He eventually granted me an out of warranty "kindness" coverage. At the end of the day it wasn't worth arguing semantics with him... Toyota covered $2700 in repairs.
Keep up with Ford and don't accept their nonsense. They can't just randomly assume that you damaged it unless their is something to support it. Get on a Ford forum and see if there is a history of failures with these mirrors. Ford would know if their was a history... makes it harder to justify their decision.