You should request
from Tesla the ownership timeline for your VIN number to retreive:
when did the change of ownership and address was performed and
who requested the change, such as a car dealer or a'new' owner.
You should also
contact your car insurance who would be able to trace
the 'other' car new owner with the swap VIN,
if you never lost your Tesla account and were still able to drive and receive software updates for example,
For
how long did you own your car and when did you discovered the VIN issue?
Did you still have access to your Tesla account since the car VIN was swapped?
And did you have a Tesla's Premium Connectivity subscription?
If so, was this also removed or not, and still pay for it?
Similarly, did you ever used a Supercharger before the VIN swap?
Can you look then at the charging history, and your Credit Car usage?
In the meantime, I would certainly
change the security access to your Tesla account,
and use multi-factor authentication. Also can you still have access to your current
vehicule and in particular
can you set a PIN number, change the speed limit or set a valet mode?
It would be very interesting to know if the VIN number was duplicated into two different accounts?
Or if the other vehicle was used without having a Tesla account if you still have access to your current account?
There is something not clear about
how your car VIN number could been used on another Tesla account?
If there was no new Tesla account, then how the other car could communicate with Tesla, for example
when signing for making new card keys and start the car, unless the other user was tricking Tesla to drive the car?
If there was a new Tesla account, and the ownership was transfered, then how were you still able to have your Tesla account
and drive your car, assuming that Tesla check for duplicated VIN when someone sign for a new Tesla account.
It seems that seems that you experienced a "title washing scam" similar to flooded car sold in an other state with a clean title.
But
I would have never think that this would be possible with Tesla, at least using someone Tesla account and not an undecleared wreck.