How to unlock my Samsung galaxy s5

What is the reason for denial? If you don't qualify, it won't be unlocked until you do qualify.

Yes, you are supposed to enter the account holder's name but what phone number did you enter? You need to enter the phone number that phone is used on, in other words your phone number. 

If the phone you want unlocked is no longer being used, that probably explains why. The ATT system should "remember" that phone used to be on your line but sometimes it doesn't. Try putting in a request as a non customer.

I had this problem also that I got denied since the phone is from 2014 and I want to get it unlocked since my girlfriend carrier is from Metro PCS and she needs a phone.