They are not CPOs anymore, they are called used now, see screenshot
Not surprised it turned out this filthy if it had been a service loaner. When my Ford was in they gave me a Jeep Enterprise rental believe it or not. Why not give me a new Ford from the actual dealership I asked, in the hopes I would buy it? Service manager told me they stopped that years ago because most people feel its their responsibility to trash it as much as humanly possible just because its free, returning it with empty tank and headliner full of cigarette burn holes. just like they take all the robes and shampoo bottles from hotel rooms.
Personally, I take great care of loaners, partly because it's right, but also for the reason if I turn it back better than I received it perhaps they give me a nicer car next time. Sure enough last time my S75 was in I got an MX P100D as a loaner.
If your Tesla sold as used, not CPO, they may have deliberately delivered it as is, i.e. filthy. But there is obviously a lack of communication and not setting expectations right if this was the case.