I could until sometime ago, (few years perhaps) check the balance of the coin on the wallet explorer site. For years it came up as 1.00 bc even though I couldn’t do anything with it. Today when I decided to check on it, it came up as “not found”.
Are you checking a Bitcoin address? If so, try a different block explorer. For instance
mempool.space.
If someone, or even that guy who sold the coins, stole the bc, wouldn’t the wallet still be found, just with no funds?
Yes. But I wouldn't use "wallet explorer" for this.
I think this issue fits better on the
Collectibles board. Have you read
Titan Mint Coins- Serious Issue- Titan Mint Bitcoin Coins ***NEW UPDATES***?