CTIA is a trade association representing the wireless communications industry in the US. They offer a short code to which you can forward spam SMS messages: 7726 (which spells “SPAM”) and it will supposedly help train telecom network SMS filters: https://www.ctia.org/consumer-resources/protecting-yourself-...
They also have resources for blocking robocalls: https://www.ctia.org/consumer-resources/how-to-stop-robocall...