AT&T data plan running out

[maldoror]

How do I go about adding data to my plan?

I thought I got a popup notice that data was running out and it was $10 to add 1GB to my plan, but I can't find this anywhere.
I have the 3GB for 30 days plan.
Can I buy another 3 for 30 plan when mine is about to expire and go from there? would i need to cancel the existing one first?

I originally thought if i went over i would be charged 15 per GB, but in the terms and conditions it says i won't have access to data once the plan expires.

 

[HobeSoundDarryl]

You use it till it runs out. Then you add another month or 3GB. If you are worried about running out before you can renew, you can always connect to AT&T via cellular to give them more money... even when you have "run out" of data.