I think what you are dealing with is mutual frustration.
I'm not placing blame, just stating the facts.
You purchased a smart phone, designed to work with a GoPhone data plan.
There are basic and messaging phones ( admittedly very few left ) for the plan you have.
It is possible to take ANY AT&T cell phone and have it work on a basic or messaging GoPhone plan.
BUT, a smartphone is designed to use mobile data, even if you limit or hobble the phone by turning it off in settings.
I'm not placing blame, just stating the facts.
You purchased a smart phone, designed to work with a GoPhone data plan.
There are basic and messaging phones ( admittedly very few left ) for the plan you have.
It is possible to take ANY AT&T cell phone and have it work on a basic or messaging GoPhone plan.
BUT, a smartphone is designed to use mobile data, even if you limit or hobble the phone by turning it off in settings.