Odd phone call claiming to be att service

I shouldn't have even answered the phone but I did. A lady with an Indian accent said my TV boxes had to be updated. She asked me for some personal information but I didn't give it to her, I asked that she tell ME who I am. She had all of my info.

But she wouldn't really update my box, she just kept me on the phone talking and repeating scripts. 

Then I was transferred to "Harry Smith" an "ATT tech" and given the number "747-224-6830"

Anyway "Harry" then kept me on the phone and was talking about a discount for my plan. Keep in mind I was told to turn everything off for this "update" and it was still off. I was told the update was in progress and I should not turn anything on. 

At this point I got an uncomfortable feeling and just hung up. This is the second time I've gotten a call from overseas support that knew at least some of my information, but who's goal was just to keep me on the phone. 

My question is - are these phishing scams? How do they know my info? If my box needs updated can't that be done without me being called? I have smart home manager and it seems like I could update it there. 

Anyway, I've had no problems other than the new updated guide, which hasn't been a problem yet other than I don't like that menu on the side but everything works ok. 

Also, the number that called me looked like a spoofed local number that did not match any att numbers on my list.