About 15 minutes ago someone managed to log in to my gmail account, and then added their phone number. I tried to follow the suggested steps but the problem is when it gets to the recovery part google says "we will send an alert to this phone number to verify your identity". That's not my phone number though, actually I never put a phone number on the account. I do have a recovery email set (and have had it since the day I created the account) but there doesn't seem to be any way to actually use it.
Is there any possible way to recover my account now that the hacker has put their phone on it?