Follow-up with whomever said they were filing it. If you have a loaner, and you're still allowed to drive it, I'd take that as a good sign (they could shut you down). Escalate it. Take detailed notes. Know everyone you talk with and when you talked with them.
Your state matters when it comes to Lemon Laws. Most states allow a free consultation (google 'legal referral service <your state>) and they'll help advise you. Doesn't hurt to have a legal opinion. If Tesla takes too long, you might have other options. Years ago, I had a similar experience with Acura/Honda. They didn't deliver on the buyback, so I sued. 1 day later they settled. My attorney said this was typical with Honda - unlike the other manufacturers, they just delay until someone sues since most will not sue - ends up being a better strategy.