Context: I live in Seattle and bought a car earlier last month, when we found the car we wanted and negotiated a price we got our loan financed through a particular lender. Fast forward a couple weeks later I noticed that my loan didn’t show up on my online banking as I already had other accounts with this credit union so I gave them a call (I thought maybe they didn’t link it correctly or something small) but they told me there was no record of a new car loan or a pending loan. So I went down to the dealer and the dealer said there was an issue with the credit union honoring their initial rate so they changed it over to chase without notifying me, I also asked for a copy of the contract and they refused. So now I’m a little frustrated and need to know more about what my rights are and what I should do next
The AG's office provides this useful guide, which reminds you that "You should always get a copy of each document you sign for your records". There is a risky strategy for getting a copy of the contract: breech the contract, let them sue you, then they will have to prove that they have a contract with you; you can get a copy of the contract that way. You won't be able to prove that that isn't the contract that you signed, in case that happens, which is why you should keep a copy of any contract that you sign.
The main legal protection that you have is (see the AG guide) that "After a deal is agreed upon and the contract signed, if you are contacted by the dealer saying they now need a larger down payment or higher monthly payments, you are not required to accept these new terms". The dealer has 4 working days to find financing and if they fail to secure financing as specified in the contract, there is no contract and they first have to offer to return your contract, down payment, and any trade-in but then they can also try to negotiate a new deal. But this is also predicated on there being a contingency in the contract like "subject to financing".
The law allows the dealer to shop financing companies, so you do not have the right to refuse to have the loan be serviced by Chase or any other business: your right to refuse regards the financial details of the loan (interest rate, duration of loan, etc.). There's no requirement for the dealer to notify you. The bank, on the other hand, will notify you.