When was it last working OK?
Are calls and texts working OK?
What exactly do you mean that internet is not working "properly"?
Is it working at all? Slowly? Unreliably? Something else? Any error messages?
Are your APN settings configured correctly for mobile data to work?
Text "APN" to 50048 and follow the instructions here to ensure that they are:
If you need to contact 48 support about this then see the links in my signature below.
