Legal Question in Business Law in California

Unless you can refinance they will continue this practice of charging late fees for the missed payment amounts. They are a business and have their own interests to think of, their advice is not exactly what is in your best interests.

Otherwise until you refinance you will have to talk to the financing company to straighten out why they charged the fees they did and request they are waived as you relied on the representations the payments were now lower.

I think it's perhaps 90% likely that the person you spoke with by telephone either gave you completely wrong information or someone failed to take some follow-up step to adjust your loan terms, and only about 10% likely that the help you got was dependable and correct and therefore the billing you're getting is incorrect. I would read your financing documents carefully, to see what it says, if anything, that might authorize you to pay less than the full normal amount without incurring late fees and interest. Hard to say how a figure of $73.11 is computed or whether it is legal.