-snip- i checked on blockchain already without unconfirmed -snip-
If it's new, there should be "
1+ confirmations" displayed below the tx, are you sure that it's a legitimate blockexplorer?
If it's unconfirmed, that guy must have used the same input to a new transaction, it's called "
Double-spending", it's possible if the transaction doesn't have a confirmation yet.
Usually, scammers time this during "
heavy mempool times" when transactions are taking a lot of time to get a confirmation (
like last week till yesterday).
Do you know the address that was used by this "
one guy"?
If you do, type it to live.blockcypher.com and it will show you the latest transactions, what differs it from other explorers is: double-spend attempts will be displayed (
in red as: Double-spend attempt!) as long as the other invalid-unconfirmed transaction is still in their mempool.