MFC not willing to renegotiate interest rate on my vehicle

Hi

I have a vehicle financed with MFC, bought vehicle in 2018 at fixed rate of 15.3%. I recently contacted MFC asking to renegotiate my rate, and they not willing to instead they told me to downgrade for a cheaper car or deposit lump sum. Like the person was not even interested to ask my reasons. Apparently they can do it because I know of someone who was assisted.