You may have to decouple iMessage in order to get sms working without data. You can try the following steps:

https://selfsolve.apple.com/deregister-imessage/

Thank you. I will give it a try.

In addition to Goran’s suggestion, you could buy a data booster, which allows data to be carried over from month to month. Messages consume very little data, and a booster should last a long time.

Thank you for the suggestion but I don’t want any data on the plan. It’s supposed to be ulimited text, I see no reason to pay for data that I don’t want just to be able to use the texting that is alreay included.