I have to agree with gadgetrants on the points made, I just didn't want to quote them in my reply.
Are you really on a 500 minute shared plan or a 550 minute shared plan? If you truly are on a 500 minute plan, you're still on America's Choice, which is old. The codes in the system should not have allowed the Droid to be activated, it should have forced you to the Nationwide. Also, if you have an old 500 minute plan, that also means you don't (and can't) have a Select unlimited text plan.
My thinking is if the above I mentioned is true, your old calling plan could be the culprit and needs some fixing up. If you don't use the unlimited text on your lines, then you need to update to the Nationwide 550 Retention Family Share plan. You have nothing to lose there and actually gain some minutes per month.
You need to dial *611 or 800-922-0204 and when you speak to CS, if you get a bad rep who says "I don't know" then you need to ask them for tech support help. If that is not offered, kindly ask to escalate the call to a supervisor who will get to the bottom of it for you.
**Edit: after I posted this I see you have a follow up message so I added to it below**
Since you have a line that does not have a smart phone, and since you are on the old America's Choice plan, it's possible the line that is using the data is the dumbphone line. It could be provisioned incorrectly or be on the mobile web accidentally. Under the old America's Choice plan on a dumbphone, data was charged against your minutes in the peak 6AM to 9PM Monday through Friday and was unlimited from 6:01 PM to 5:59 AM Monday through Friday and unlimited on weekends. Look over your bill and see if it is the dumbphone line that is causing the problem, and if so, then that's it.
Bottom line - update to Nationwide plans.
I speak this from a former CS rep side of things, not just guesses.
Are you really on a 500 minute shared plan or a 550 minute shared plan? If you truly are on a 500 minute plan, you're still on America's Choice, which is old. The codes in the system should not have allowed the Droid to be activated, it should have forced you to the Nationwide. Also, if you have an old 500 minute plan, that also means you don't (and can't) have a Select unlimited text plan.
My thinking is if the above I mentioned is true, your old calling plan could be the culprit and needs some fixing up. If you don't use the unlimited text on your lines, then you need to update to the Nationwide 550 Retention Family Share plan. You have nothing to lose there and actually gain some minutes per month.
You need to dial *611 or 800-922-0204 and when you speak to CS, if you get a bad rep who says "I don't know" then you need to ask them for tech support help. If that is not offered, kindly ask to escalate the call to a supervisor who will get to the bottom of it for you.
**Edit: after I posted this I see you have a follow up message so I added to it below**
Since you have a line that does not have a smart phone, and since you are on the old America's Choice plan, it's possible the line that is using the data is the dumbphone line. It could be provisioned incorrectly or be on the mobile web accidentally. Under the old America's Choice plan on a dumbphone, data was charged against your minutes in the peak 6AM to 9PM Monday through Friday and was unlimited from 6:01 PM to 5:59 AM Monday through Friday and unlimited on weekends. Look over your bill and see if it is the dumbphone line that is causing the problem, and if so, then that's it.
Bottom line - update to Nationwide plans.
I speak this from a former CS rep side of things, not just guesses.