Just a billing/customer name but no address. Email communication goes via Amazon so they can cut you off from the customer and also so they can remove email addresses and link, but they can't do much if a seller wants to call up or send promotional material in the package.

Hmm, I see. In the past I ordered what ended up being a scam/"mistake"-priced item on Amazon, and I left negative feedback for the seller seemingly purposely baiting & switching customers by pricing items substantially low, cancelling the order on them, and offering them a store discount if they remove the negative review (this appears to be their long-term MO, as per the countless other reviewers experiencing the same bait & switch). A rep from the respective store actually called me on my cell phone, which is not listed in my shipping address (and is not in any public listings anywhere). Amazon should be more upfront/clear about what information is actually passed to a seller on their marketplace (ignoring manually scouring through EULA/ToS).

Yeah the only reason Amazon provides the phone number is because a lot of carriers require a number to be on the label.

There are some rules around it listed here: https://sellercentral.amazon.com/gp/help/external/200386250 But yeah, it is going to be a hard one for Amazon to enforce unless a number of people complain about a seller.