[c3534l]

From your own admission, they block accounts known to be abusive. I don't know how that's compatible with "don't care" and "don't investigate" - neither of which sounds like something Microsoft would plausibly tell you. What are you basing this impression on?

[yardstick]

Microsoft blocking accounts that are the source of abuse reports doesn’t necessarily mean Microsoft has investigated for themselves the validity of those abuse reports. At least that’s how I interpret what the op was saying.

I would hope they did investigate too otherwise it’s too easy to DoS a valid customer with fake complaints.

[efitz]

For a lot of reasons, cloud providers will never tell you how they investigated or what they found out. Telling you only has downside - either they give away information about tools & techniques, or they leak PII of other customers, or you engage them in a protracted discussion which will suck time away from addressing other abuse complaints, etc. So you will never get detail. That doesn't mean that they didn't do anything, it just means that there is no upside for them to sharing details with you.