my iphone wont let me turn on my cellu.lar data.

Hello antmann254,

For difficulties with your cellular data you'll want to take the steps below:

• Check your coverage area
• Restart your iPhone
• Check for a Carrier Settings update
• Turn your cellular line off and back on
• Reset your Network Settings
• Update your iPhone
• Contact your carrier

You can find more details on each of those steps in this resource: If you see No Service, Searching, or SOS on your iPhone or iPad - Apple Support

Should that still persist, you'll want to reach out to Apple Support: Apple Support They'll be in the best position to look into this further.

Take care.