So this has been occouring for a while but i do not believe that this has been bug reported surprisingly. I believe back in the day there was a option to choose between the email and phone number but now there is just a email option. The message clearly states that you can still use a phone number while thats not a option anymore:
Hey @13_5G, thanks for the report. This was indeed a mistake on our end. We’ll be bringing this back as soon as possible. I’ll update the report here once it’s back.
If you need to recover your account via phone number, try this link for the time being: Roblox
Thanks it appears now! Just a small thing i noticed is that it says “Continue” instead of “Submit” in the phone tab. I don’t know if this is intended or not but possibly since it’s the same in the reset password page