dealer sent me the pink slip to new car ... is the car mine now since
they made a mistake and sent it to me throught the dmv with my name as
owner of car?  should i stop making payments since I now have the pink
slip

Even though they may have sent you the title, you still are legally
obligated to make scheduled payments on the car.  By not doing so, you
voilate your purchase agreement and leave yourself open to
reposession, legal procedures, wage garnishment and many other end
results.

Nothing is free in life.  Especially not a car.