Can you please provide a little bit more detail so we can help address your concern. Are you unable to access data on your cellphone? Do you currently have a wireless plan that includes data? What device are you using? If you have data included in your plan but you're unable to access it I'd recommend you to check and see if you've used up the data for the current bill cycle. I would also recommend you to reboot your device to see if it fixes the issue for you. Alternatively you can also reset the Network Settings.