Samsung S23 Ultra no mobile data

[Fieldmouse48]

I bought a second hand Samsung S23 Ultra for my wife. The seller bought it in the States, so it is an  AT&T phone.
It is on a One NZ prepay plan, which is current.

It worked initially, but suddenly there is no mobile data.

She can make and receive phone calls and txts, but cannot use anything that requires mobile data.

Wi Fi is OK.

One NZ staff in a shop couldn't figure it and nor can Samsung Online technical help. Samsung suggested that I contact AT&T.

Any thoughts?

Thanks

[inspired_chef1975]

Go to One NZ website. They will tell you how to setting up. 😊😏 Each of mobile brand. Other than that phone has to be unlocked from the one you bought

[NightSkyPhotography]

Unfortunately you buy second hand that's what you get. Send it back to the seller. I've been through mucking about with phones to the point I will buy new as it's not worth the wasted time and stress.

[DamienJ]

You can go here once you download to your PC you can turn mobile data back on through there
https://samfw.com/