All Bitcoin transactions are irreversible, regardless of where they were done. Only the person to whom you sent them can send them back to you. Therefore, it is impossible for LocalCoinATM to provide you with any kind of refund.
Bitcoin can detect typos, and will prevent you from sending money to an invalid address by mistake. However, you should always confirm that you have the correct QR code/wallet address before scanning it into the machine.
Also, do not send bitcoins to anyone threatening you for a ransom, or who claims you owe money to the Canadian government. They are scammers. Hang up the phone, and call the police if anyone like this contacts you.