It could be because you received one last year and the information got transferred from last year. If it's not, I am not sure why you are prompted to the form. However, it is an easy fix. If you have not filed, you can simply remove the form. Here are the steps (online):
- Sign in to your account, select Pick up where you left off
- To your left, select Tax Tools, click on the drop-down arrow
- Select Tools
- Under Other helpful links, choose Delete a form
- Scroll down the list to locate the Form 1099-G, select Delete and Continue with My Return