Xfinity chat asked for SSN and Birthday for Phone promotion - is this legit?

I am freaking out right now. I was using the Xfinity chat and the agent brought up a promo to save on my bill and asked for my phone, and a 'secure' link to enter ssn and birthdate. I was not thinking at all and entered that info and now I am wondering if I just got scammed to give out my social security number and birthdate. Can anyone check to make sure the link I got and the chat was legit? Base of the link was: https://iguard-po-1pp.slb.comcast.com:9443/

Thank you, please let me know!