I purchased a 2016 f-150 from Cornerstone Auto, even though they lied to me about what they would include in the sale, back in 2016. I then purchased an extended warranty in 2017 and was told that after my 3 year 36,000 mile factory warranty was up the extended warranty would start. Upon trading in my 2016 for a 2018 I was told that my extended warranty would be refunded in full as the now 24 month old 2016 truck had only 16,320 miles on it and therefore had not started the extended warranty yet. 3 months later I receive a refund check for only 2 thirds of the original price with an excuse that the extended warranty was pro-rated from the purchase date and because I didn't have the original statement in writing I have no recourse. Not that I was planning to purchase from Cormerstone Ford ever again, I will now never return for so much as air in a tire. Crooked sales managers and finance managers. Buyer beware that short of having an attorney review or have the exact verbiage added don't trust sales at Cornerstone Ford.