Do you get a data icon such as 4G / 3G in the phone's top status bar ?
If not pull down your top notifications shade and ensure the Mobile Data is toggled On.
Also make sure no data limit is set in your phone's settings.
Settings. Connection's. Data Usage. Billing Cycle and Data Usage.
May I ask are you not able to access the Internet in one area or everywhere.
If nkt in one place then please check any relevant Mast checker your network has to see if there is any known issues being reported.
As a process of elimination can you try your sim card in another phone and another sim card in your phone.
Daily Driver > Samsung Galaxy s²² Ultra 256Gb in Phantom Black.
The advice I offer is my own and does not represent Samsung’s position.
I'm here to help. " This is the way. "