WestStar Credit Union Bank scammed me with a car loan Las Vegas Nevada

My husband applied for a loan through WestStar Credit Union.  He was preapproved for $30,000 at a rate of 14%.  Zachary, the Financial Services Representative for WestStar, contact my husband with the information.  My husband denied the offer as he was also preapproved by Capital One for a rate much lower.  Zachary then offers to beat Capital One's rate and provide a rate of 6%.

My husband and I then go to search for a car keeping in contact with Zachary as to what steps we take next.  Zachary sends a preapproval e-mail and a form to give the car dealership.  We decide to sell our car and use the money as a down payment for the car.  We ended up purchasing a car far below the $30,000 that we were preapproved for (Out the door cost:  $18,383.00). 

We purchased a Used 2010 Car on October 3, 2014.  On October 8, 2014 we receive a call from Zachary stating we were denied the loan at 6% and it has been raised to 14.99%.  Nobody at WestStar Credit Union could do anything about it accept to suggest that we take the loan with Capital One instead.  ALL the decisions that were made by us were based on WestStar preapproving us at 6%.  If we knew we had to go for Capital One, we would have purchased a newer car as the rate with Capital One increases based on the year of the car that is purchased.

I can imagine this scam being done by car dealerships but I would never imagine this being done directly by a financial institution.