Desbloquear iphone fora de contrato

Comprei um iphone5 no ebay há 2 anos. Entretanto o telefone ficou elegível para desbloqueio. Pedi o desbloqueio no site da at&t e responderam! (order @ ecom.wireless.att-mail. com) Enviaram um email a dar intruções para completar o desbloqueio:

Thank you for contacting AT&T about unlocking your mobile device.

Congratulations! Here are your unlock instructions:

For iOS 7 or later devices, please turn off Find My iPhone before unlocking your device.

1. Open iTunes on your Mac or PC and verify that you have Internet connectivity.

2. Ensure the original SIM card that came with this device is inserted in your iPhone.

3. Connect your iPhone using the dock connector to USB cable that came with your iPhone.

4. Backup and restore your iPhone using iTunes. For information on backup and restore, please visit http://support.apple.com/kb/HT1414.

5. After restoring, your iPhone will be unlocked.

No passo nº 2 diz para inserir o cartão original at&t (que eu não tenho). Como posso resolver isto sem cartão?