Where do you get the data about spam texts being internal to MNOs these days? I keep track of the ones I receive and they're almost all going through third party companies that are themselves sending through Twilio, Bandwidth, Sinch, etc. This makes perfect sense to me given what I know of the market and how spammers operate.
Manually. My MNO does pretty aggressive blocking, so I only have about 1/week to deal with. That's low enough that I report them manually rather than try to automate the constantly changing reporting process or deal with app development. The response is almost always some variation on "We've forwarded your report to the network we received it from".
