Account security

I believe my account was hacked.  I cannot access my account.

Yesterday, I received an email from Peacock indicating that I had signed up for the service -- I did not sign up for Peacock. 

 I did not enter account specific details in response to the email, and in any event I cannot now access my own account via Xfinity. I cannot, for example, look at my bill or account information. Instead, the platform sends me into a loop of entering the Xfinity security code(s) texted to my phone, retyping login info, and then starting again and again.  

Help?