Why cant i access my google account on a new phone when I have not factory reset my old phone

I recently bought a LG Stylo 3. It is the EXACT same brand and model of my old phone. I bought a used phone from Offerup but I know it is not locked. The person who sold me the phone did a factory reset to it right before selling it to me. I called Metro PCS and activated the newly bought phone. I tried to sign in to my google account and i entered all the information correctly. but it tells me i have to wait 24 hours before attempting to sign in again. I waited 24 hours and the same message prompted. I waited 72 hours and the same thing. How can I prove I am the owner of the Google account and allowed to use my new (used) phone?! I am frustrated because Google does not have a service to call or even text. The phone is not locked, I have all the informations and I can still access my information easily on my old phone. Can I add a new device to my google account before activating it? Essentially this is not an issue of a used or new phone, it is an issue with my Google account and thus if my old phone (that I am forced to use) breaks then I am completely screwed. How does Google have a multi billion dollar business if they dont have customer service help??