My problems with LaMesa RV San Bernardino were only resolved after I had an attorney contact the main office in San Diego on my behalf. That was in 2005, I guess from your comments that not much has changed. As far as renewing the extended warranty, try WholesaleWarranties.com, or even Good Sam. Deal with reliable people who will give you service when you later require assistance. Hopefully you do not have claim at this time, so get a new policy from a different supplier, and gather all your paperwork, and take them LaMesa to small claims court for a pro-rated year of warranty that did not exist.
JMHO Good Luck.