Apple Watch Pairing Error

I recently got an Apple Watch which was used by my sister before. I reset it and I tried to pair it with my phone. My phone said it has activation lock and I need to sign into c******@gmail.com. No account like this existed. I’m sure of it. I asked my sister she didn’t know, I tried emailing it, doesn’t work. If I try to login on the Apple Watch app it says the account is locked. How is it locked if it never existed. And even if it did exist how would I unlock that account. No devices were already signed into it.