Well, it sounds like you're unhappy, but I think it's mostly confusion on your part.
Actually, you didn't comment at all on picking up the car. I'll assume you went to the Fremont delivery center. Everything probably went fine or you would have mentioned a problem. Me, I had one of their Ludicrous Latte drinks, so I had such a buzz on I wouldn't have noticed any problems.
So was there any issue? Sounds like there wasn't. Usually the only message you see is that it's limited for one reason or another. Is that the message you saw? It's not an "issue", it's merely informative. In any case, the message went away, right?
Plugged it into what? There could be a problem with the charging source, the cable, or the car? Any idea which? Had you ever used this charger before?
I think you're probably confused again. Sounds like you got a message that a firmware update was available. There's no error. You don't have to update if you don't want to. There is no problem. No, there's no reason that the update should have been done before. Did you tell it to update? Did it not work (as you say later the firmware isn't updated)? What's your firmware version now?
Don't know. Sounds concerning. My Model 3 has sometimes had excessive vampire drain, but not that bad. The more usual thing is that it runs my phone charge down overnight. I'm guessing there's excessive communication going on. The software's still pretty rough, so I've been assuming this problem will get better soon. What firmware version are you on? You should be able to see the version at the bottom of the screen for the car on the phone app.
Sounds to me like the car is driving fine. There is no reason to care whether the firmware is updated. You haven't even tried to charge it from a known good charger (or supercharger). So you have no idea whether the car is the problem or not. It's not "bricked" in any way.
Okay. So the one obvious thing to try, charging from a known good charger, you didn't try. I think you should have asked them to try that immediately. I'm sure they would have freed up a charger for a test. This means you still have no idea whether there's anything wrong with the car. The only actual problem you've seen is excessive vampire drain overnight.
And it sounds like they took your car in for service and gave you a Model S as a loaner. Good deal!
Okay, seems odd to pay Uber to take you to the service center without calling to find out what's happening with your car. And what happened to the Model S they gave you?
Escalate what? Take a look at your phone app to see if the battery has drained excessively further. Call up the service center and ask them if your car can charge using their charger. Ask them if they know if there has been further excessive vampire drain while it's been there. Ask them to please make sure the latest firmware is installed.
Right now I can't see any evidence that there's anything wrong with your car. There might be, but probably not. What's wrong is that they didn't educate you about ownership. That part clearly needs work.