Question Most cost-effective way to make a few calls and send messages from Samsung watch?

Thanks for taking a moment to check out my post.

I use a wheelchair, and I am looking to set up a smartwatch as kind of a safety device.

I'd like to be able to use it to make calls or send messages if I get stuck or fall.

Hopefully, I would not be making calls or sending messages directly through the phone very often.

I am wondering if I can find a way to set up a small prepaid plan for the watch. I am looking to keep my expense on this one minimal.

Even though it's important. I don't think I would be using the watch as a standalone communication device very often.

I went to a local T-Mobile store this afternoon. They said I had to have a traditional phone line and a number line for the watch.

Any advice would be greatly appreciated.
Tom