Help to unlock

I have iphone 5 smartphone and put unlock request [edited for privacy-please do not post personal or unique information such as but not limited to full names, employee ID numbers, email addresses, phone numbers, account numbers, etc.] on AT&T unlockportal. Then i received unlock confirmation from AT&T:

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.
Additional information on unlocking can be found at http://support.apple.com/kb/HT5014.
Questions? Please call 800.331.0500, or dial 611 from your AT&T wireless phone.
Sincerely, 
The AT&T Customer Care Team 

I did everything according to instructions. But phone is still locked and doesn’t work with my SIM card. I can’t activate phone. Please, can you help me.

Thank you for your business.

Have a nice day!

My Best Regards.