Ordered two oil filters (one for each car) and a g...

Ordered two oil filters (one for each car) and a gas cap. Received the oil filters, but instead of a gas cap, RockAuto shipped a throttle position sensor (for a car I don't even own). When I contacted them to this corrected, I was told to ship the incorrect part back (using their FedEx account) using my paper/ink and drive it to a FedEx shipping center. Once received they would ship the correct part to me. This sounds like a ransom situation. Why not ship the correct part to me first and provide a shipping label to return the wrong part? This is what most companies do. While I've enjoyed their service in the past, unless RockAuto changes its policies, I won't be doing business with them anymore.