Nissan of Melbourne so anxious to make a sale. I was lead to believe ins. was transferred. it was not Melbourne Florida

 You need to see a lawyer ASAP, and when you do there are some things to think about.  It may cost you a few hundred dollars, but if they can figure out a few things it may save you thousands.

First of all there appears to be no financial incentive for the dealer to lie or make a fake calling the Insurance Company.  But it would also be odd that your insurance would talk to them without verifying who you are.  In fact it would actually be to their financial advantage to instead of transfering the insurance to sell you new insurance.

In many states it is illegal to allow a car to be driven off of the lot without insurance, but as you found out there in most cases is a 30 day window you have to transfer it over.  So as long as you had proof of current insurance that would have been enough.

So could it be a possibility that the dealer only called to verify current insurance?

Now some oddities, it would be very..very unlikely that your insurance would be exactly the same cost.  So when the salesman called did he also tell you anything about your new rate?  Also, you will notice on your insurance card it shows the vehicles covered.  Those are sent out within days of a change, did you not notice you did NOT receive an updated card with the one car taken off and the new one put on?  Along with that an insurance company will send you out a new summary showing the reason for the change in rates.

As for the accident, I am figuring that you are saying you were at fault.  As if you were not at fault it would in most cases be the other party who is responsible for the damage regardless of your insurance status.

In the end the dealer could be your "best friend" in being a witness that in fact they did contact the insurance company and have proof, or your "worst enemy" because they lied and could be responsible for the entire thing.

Good Luck.