Target Gift Card Scam

I had a frustrating evening last night with the Target Gift Card Scam. Mercifully I did not fall for it - but the amount of information they have from the Xfinity system is really, really concerning. Did Xfinity have a data breach? I have 2FA on my account, but this team knew my address, my account number, my bill, they even made some pretty convincing texts and emails coming from Xfinity addresses to sucker me in.

For those that haven't seen this:

• They call and leave voicemails warning that because you haven't taken advantage of the new promotion your bill is about to double
• When you call back there is a long menu tree that seems pretty legit
• They know your account, they know how much you pay a month, and tell you that your bill is about to go up unless you take advantage of a new promotion
• They state that no contract is required and that they can set you up over the phone, it will half your bill, but you need to pay for two years up front
• They generate a code and then authorize a 9.99 payment. You get a text from the usual Xfinity number and an email from the usual Xfinity email about this authorization
• Then the kicker - this promotion is sponsored by Target and the payment can only be made by a Target credit card or Target gift card
• This payment also needs to be made by 9PM tonight or else you will get a $400 contract cancellation fee and they will shut off your internet for three weeks
• At this point I'm pissed and ask to speak to a supervisor, I just don't want to deal with it because I'm not getting a Target credit card nor do I want to drive to a Target and I don't understand why on earth we can't just pretend this conversation never happened. They put me on hold for a moment, then the same guy hops back on and says he's the supervisor. 
  • In retrospect this part was pretty funny. I didn't want to be insensitive / racist, but after a few moments pause I asked if I'm speaking to the same guy
• Finally I wise up and hang up.

Sharing in case other people run into this. But how on earth do they have all this information on us? How are they sending official Xfinity emails that are signed by alerts.comcast.net, and their texts are from the same ID that Xfinity usually uses?