Agent asking for my SSN. Is this a Scam?

I was trying to reduce the rate of my bill through talking with a live agent named Jinial. They offered me a deal that said if i signed up for a new phone line my bill will be initially cheaper by ($50) for 24 months and i recieve a new phone as well. It seeming too good to be true i asked for some type of contract or agreement and they sent me a outside  link to which prompted me to enter my SSN and other personal information. why would they need this information in the first place? is this a legit deal? seems very fishy to be honest