Most legit providers offer filter rules you can configure as you need. Particularly if you're using a paid enterprise service. You could check to see what rules a provider has available and if you can block by MX record or IP. You wouldn't need to control the server, just have a provider that let's you customize your needs.
Unless you are intentionally finding services that do not use M$ infrastructure then you risk losing a lot of access. Flights, trains, hospitals, schools, stores, events may all use M$ as a provider whether or not they are sending from their own domain. Personally I'd rather receive my tickets that I pay for than not.