No probs
I don't think Tesla took you for a ride if you had the tow package installed after purchase. There is a big bar behind the rear bumper that is the width of the car and bolted to each corner, plus a wiring harness. I suspect $1250 was for the purchase and installation of the whole tow bar assembly and required some time to do given they need to remove the rear bumper.
My car came with tow package from factory but with European hitch, not 2" square which is the common hitch here in Australia, like the US.