Good luck with this one, don't let up on them once Ford service calls you back. Hopefully, they will contact you after this letter.

If you get no response here, try another dealer to get them to look at it. If no one will, ask for a meeting with the Area Warranty Manager. I am not sure about Ford, but GM has this position. He/She is the guy that monitors the dealers to make sure the warranty jobs they are doing are legit and they aren't costing Ford extra by doing jobs for free that should not be warranty. But you could try to plead with him/her. If Ford has such a position, but they have to report to someone in Ford for warranty work, since Ford is picking up the tab and paying the dealership back.

Good luck!