They developed AppleScript for people to do this individually, at limited scale.
Push notifications, attached to an application or website, and controllable by a user on that basis, are the solution for corporate messaging at scale.
This will get you banned. It’s not a question of if, but when. Users will hit the report spam button. Apple will shut you down.
Are you telling me that the “report spam” button actually does something??!?!?!!!
People don't report our phone lines to be spam because the use cases that we focus on are either mostly inbound (e.g. customer service, the user is the one who texts first) or warm opt-in outbound (e.g. form-fill text back or follow ups). Businesses want a better medium to communicate with their users and users want something more conversational and native to their messaging behaviors.