Exploring the first site at India was 174 k after the upgrade, but dropped within an hour. I don't know how far you were, but I upgraded England, unlocked Italy and Egypt before the upgrade, but haven't upgraded them to 2 stars. My most expensive one was exploring the final site in India (between 2-3 k, but my trades are up to 330 coins as everything else is at 5*).
Are your still at 10/20 k for the 2* upgrade?
I would say if the price impossible, submit a ticket.
Btw. Can you still find keys/autofinds?