I would call the nearest Forest River Dealer to you and explain that the Dealer that you bought your unit from closed and see if they would do warranty work for you and ask about the extended warranty that you bought. If the Dealer that went out of business pocketed the money for the extended warranty, it would seem that no other Dealer would honor a warranty that does not 'exist', even though you did pay for it. You may now have become a 'creditor' of the closed Dealership and to say it out loud, they stole your money and it will be difficult or imposable to get it back. I would talk to your 'new' Dealer about an extended warranty, but you will most likely have to pay for it (again).
Other Forest River Dealers can work on your Wildwood, even if they do not sell them. Find the closest FR Dealer to you by putting into the Dealer finder a different FR line and work you way through the list until you see a Deal that is closest to you.
2013 Forest River Salem Hemisphere SBT312QBUD
2001 CrewCab F-250 7.3 PowerStroke Diesel
SuperChip, BTS transmission, 6.0 Trans Cooler