You can unlock your phone after you bought it from ATT. I have read how to do this here, and it have been very helpful.
Just use Att.com/deviceunlock to request a code. This works for customers and non-customers. If you use an unlock service you can try swiftunlocks or attunlocker.us to buy a code for your Samsung Galaxy
I Brought s9 plus sm-g965u from Att with fully paid.
I unlocked it using ATT portal.
Issue starts now, once i unlocked i changed my network to Tmobile.
After few weeks, daily few calls are dropped and goes to voicemail. (Dont tell network issues for T mobile)
I am facing nearly 10 plus daily calls are dropped. I tried reset network settings. Factory reset. Change the sim. None of them worked
There are lot of people facing it
With this device model
No technician knows whats going on.
Some says maybe problem with sim, signal most stupid answer is maybe you put Tmobile sim in att device. When i say its unlocked no response.
I tried to contact samsung they says our technician will solve it
If ATT PEOPLE ARE HERE OR TMOBILE.. SAMSUNG PEOPLE TRY TO RESOLVE IT.
WHY CANT I RETURN THIS MALFUNCTION DEVICE AFTER USING 2 MONTHS.....SAMSUNG? EVENTHOUGH IT HAS ONE YEAR WARRANTY?
DONT EVER BUY ATT PHONES....
It's best to purchase thru your carrier than thru samsung (to get an unlocked device)? Trying to best the Note 8 at the cheapest rate possible.
Carrier/sim Unlocked is NOT the same as getting a Truley unlocked Phone from Samsung..Samsung Unlocked has all Radios in it and has No carrier bloatware..