San Juan Credit Union in Southern UT along the UT/AZ border?

My husband is trying to sell his truck and we have a couple who have allegedly taken out a loan through San Juan Credit Union in Southern UT. From what I can see, via the website a href="http://www.sanjuancu.com/" rel="nofollow"http://www.sanjuancu.com//a , I feel like it is a legit bank. Is this accurate? I am worried because the people that are buying the truck said that San Juan wired the money to my husbands bank and my husbands bank is saying that a check would be expedited to them. The details are confusing we have no way of getting ahold of the bank tonight, and tomorrow is looking grim. The buyers want 'their truck' and we are uneasy about handing over the keys if a check hasn't been received. The truck is insured, (we are still paying on it,), and has gap insurance as well as American Family Ins. If we were to hand over the keys and it turns out that the 'sale' is illegitimate, what do we do? How can that affect us and what about our payments to the bank, etc? Please help