These wallet.dat scams are so ridiculous. Like how in the world do people think some body will sell a 31 thousand Bitcoin worth of a wallet.dat if the file is recoverable. How do they guarantee you are the only owner of it. They can send you the file and they will continue to have access over it among every body else who may have purchased it.
Let's even assume there's Bitcoin in the wallet and the seller gives you the seed prase, why is anybody buying a wallet? Why not just download a wallet and buy Bitcoins? Better still, why no just buy the coins from whoever wants to sell?
Any information is appreciated !
A lot of users have already told you "you've been played" and that's pretty much the whole truth.
It's really unfortunate that people still fall for things like this. If you don't know anything about Bitcoin or crypto, then why is buying your first step? Because if you had any basic understanding or knowledge of Bitcoin, you'll know to stay away from scams like that.
A lot of users here have fallen for one scam or the other at some point in their Bitcoin journey (mainly the beginning), so you're not the first. Don't beat yourself up.
The lesson learnt and how you handled things like this in future all that matters right now.