This is about Google Workspace, a higher tier paid account which does include phone support. Equivalent to if someone like your business ISP called you (or someone else who you are a paying customer of, with real phone lines). That being said, it is mentioned that OP doesn't pay for that or Google One.
I am a paying user of Google Workspace, and also run a charity that is a user of Google Workspace with thousands of accounts. The account they were trying to phish was a paid Google Workspace email.
