Hello I have bought an iphone X from Wallmart and paid all full amount for using the device globally. I have now Tmobile Sim in it and it's working but when I put any other sim it's not working. I assume still is Carrier barred. I called your Support also and gave my imei number and email address and told me that they will send me email in 24 hours but have not received any. Let me know now what I have to do to use the mobile globally. I wait for your early reply ASAP. Now I am not in state so I can't call you frequently but you could message me or email any time.
Welcome to Apple's 3rd party flex reseller policy.
Apple sells phones to 3rd party resellers under the assumption they are unlocked but once the first sim card
is inserted into the phone it lockes the phone.
To get an unlock code from Tmobile you need to meet the requirements in the link below.
If you meet the requirements then your best bet is to contact Tmobile through facebook and have the reps contact Apple
to get the imei# logged into Tmobile's system.
Manage your T-Mobile account