Within those steps you listed above, when did you ask Tesla to change your payment option to Tesla Financing? Also, when did you apply for the Tesla loan (and get the standard 2.49%) in the steps above? It almost sounds like you submitted your DCU loan doc for the rate match before even applying for a loan through Tesla.
My understanding is that you need to apply (and get approved) for a loan through Tesla, and then you submit the DCU loan doc with 1.24% to
[email protected] and have them match the interest rate with your 'new' loan through Tesla.