Wifi password

I recently switched to prepaid plan. I can't change my wifi password. On app I am getting info that "

WiFi credential settings are currently unavailable

​We cannot display your network name and password because your device does not support this feature."

I also tried to do this on admin tool (10.0.0.1). I doesn't work either.

I spoke with multiple agents and technitians. All I am in response is article on 10.0.01 admin tool method.

Why I am not allowed to use basic and most important feature, which is wifi password change?

Is there anyone competent in your company that knows how to fix this problem?

Kind regards