Cannot connect with my cellular. It disappeared.

Hi joannefrommilton,

Are you referring to setup your cellular data service on your iPad Air or referring to restore your whole iPad Air?

If you are referring to setup your cellular data service on your iPad Air, pls refer to this link: https://support.apple.com/en-sg/HT203089

If you are referring to restore your whole iPad Air, here’s how:

Make a backup of your iPad Air using iCloud or iTunes, you can refer to this link: https://support.apple.com/en-sg/HT203977

Then you reset your iPad Air to its factory settings, you can refer to this link: 

https://support.apple.com/en-sg/HT201252

After that, you can restore your iPad Air from a backup (iCloud or iTunes), you can refer to this link: https://support.apple.com/en-sg/HT204184

Hope these helps 

Hello,

Which model of iPad do you have?