Ugh 2 TB flash drive? Do you mean a USB thumb drive or an SSD? Generally, there is no such thing as a 2 TB thumb drive, they are all fake! When you fill up the actual capacity of the drive, it writes over the beginning, which contains the file directory, and kaboom! it all get scrambled. That may be recoverable. If the remapping table is corrupted, it might not.
Yes, I think from context that OP has been had. I hope that USB drive didn't come from Wish dot com…
A 2 TB USB drive is built like a brick and costs anywhere from 300 USD to 1200. 128G drives are beginning to be affordable and 512G and 1TB are not unheard of, but understand that two terabytes is a lot even for full-sized hard drives. We're not living in the future we thought we'd be in the nineties. We're encountering hard walls in advancing our technology, so the rate of advancement, which used to be quadratic, has declined sharply.
If something seems too good to be true, it probably is, and that goes double when you're buying from faceless sellers in an international online marketplace. Right now, a lot depends on the actual size of the flash drive and how much you tried to put on it. If it was a fairly large drive before they “dolled it up”, say 64 gigabytes, and you tried to put maybe 100 gigabytes on it, there may be a decent amount that was not overwritten. But if it was 16 gigabytes, your data is largely gone. That's just how it is.
And recovery is difficult. Computer file systems are a miracle of technology and when they go wrong, when the computer can't tell what's what in a mess of data that used to be some files… it's a problem neither humans nor computers are terribly good at solving.
Sorry I couldn't be more help.