My service plan was deleted within a couple hours of service

I clicked on a different service plan to see details and my plan was deleted.

Do you mean you accidentally signed up for a new plan?

I had already selected a plan and my phone was working. I was looking at a different plan that had more hotspot. I’m not sure how it would have changed what I signed up with using a prepaid card

Prepaid doesn’t refund. 

When you selected change plan, and then went through with the change, you had to pay for the new plan in order to continue service. What you did essentially was to throw away the plan you paid for.

This is why AT&T has little pop-up Red Letters which tell you to wait to the end of your 30-day cycle to change your plan so that you don't lose the service you have already paid for.   Look familiar?