Was persistent in calling me multiple times to say I'd won $800+k

A Mr. Williams who says he's from Georgia, but calling from a number showing on caller id as from Kingston, JM (876-367-4551), said that I'd won a big prize. When I told him I don't trust many out of the blue phone calls especially from Kingston, JM, he said he'd have his manager call me from the bank itself to talk to me.  A phone call from a woman a bit later who was showing as "Private Caller" on Caller ID called later.  I started googling "American Megamillions" which came up first as a lottery scam link and I said goodbye and hung up.  Read further and it was talking about emails being sent to people from this entity, where I was called on the phone.  Anderson called me back and got upset that I'd hung up on his manager.  I told him that I'd listen to him more, but wanted to have more time to research his company, on the chance that he was legit and their normal methodology was calling people and that the scam was someone trying to impersonate him with emails.  Found this site and verified that the phone calls look to be scams too and hung up.  He's called multiple times since then, but hung up eventually.

He had earlier tried to ask if I'd shopped at Walmart or some unknown pharmacy to me that would have gotten me enrolled for this lottery.  I told him that I don't shop at Walmart, and that I currently don't get pharmacy orders from a local pharmacy any more, which wasn't the one he mentioned anyway.  So, those are the things they will try to do to make it sound "legit" I think.