I've been waiting four years and counting... Model X reservation. Every time I call, I get a new person (Because the last person I talked to doesn't work there anymore) and they swear that they will certainly solve this for me! And then I never hear from them again.
I got mine back without issue shortly after they made them available to order. I wasn't convinced it was for me then but I've changed my mind recently and now i'm looking to buy one again. I had no issue receiving a paper check for the original deposit.
Damn, that sounds terrible, sorry to hear. Maybe your reservation is old enough that it got borked in a schema migration or something. Good luck getting it fixed, maybe it's time to threaten legal action.
I suggest you get on that. Next call you get will be, the VIN is issued, sorry no refund! File a small claims case if the refund is less than small claims max. File a complaint with your district attorney's consumer protection division. File a BBB complaint, Tesla is a member looks like. Squeaky wheel and all, but hey it's your money.