Hi,
sometimes they have delays with transactions. You even can wait up to 3 days with "pending" status of your transaction. But don't worry you will get your money OR they will send it back. So sender will need to re-send it.
Please read the whole thread before posting, the transaction is already confirmed and it shows on the ledger already, the problem is it never shows on his wallet(which is blockchain.i) so there's no need to wait up to 3 days with your "pending status".
Anyway don't worry. It is impossible to lost bitcoins.
Who tell you that?
@OP and as what I see from your receiving address the 12 btc was sent already to other address I hope it was made by you.