Hi @Ilblo, welcome to our forum!
I think this question is best suited for your operator to answer as the device only really cares if the SIM card is activated or not. If mobile data is disabled by your operator but you pay for unlimited data, there is nothing that can be changed in the device for this to start working.
The device only needs the Internet settings (APN) and these will tell the device what settings to use when you want to use mobile data. If you haven't downloaded these, you can do so in Settings > More > Internet settings > Accept. Once they are downloaded and installed, restart your device.
I hope that helps!
