Your credit history is your financial reputation. If you don't have a good history of handling your financial responsibilities, then why should USAA trust you to repay the loan. There are places that will accept the risk of loan money to those with bad credit - USAA is not one of them.
How is Equifax any more or less accurate than the others. If something is incorrect in your credit report there is a procedure to have it corrected.
I have responded ot your other post here, but wanted to offer an additional outlet to share your disappointment. If you send us a message here with the details of the situation you are describing, we can get a bank specialist to review your account and see what can be done. Thank you for posting.