You'll need to post a bit more information than that if you want assistance from the Community Forum.
When was your mobile data working ok last?
Do you have an active membership plan with a non zero mobile data allowance?
Are calls and texts working ok?
Are your APN settings configured correctly?
If you're on Android you can text "APN" to 50048 and follow the instructions here to do this:
If you need to contact 48 support about this then see the links in my signature below.
