To your first point, Facebook has clear policy against sending a marketing message more than 24 hours after a user messages in. They just haven't been enforcing it. You can definitely report them in the app.
With SMS, in the US, it is illegal if a company is sending unwanted texts. Covered in the TCPA - Telephone Consumer Protection Act ~2015. Any legitimate provider will automatically opt you out of the campaign if you reply STOP. You can also copy the text and forward it to the number that spells SPAM (7726). They will send a bounceback and ask you what number sent the message.
It's super cludgy, but the carriers do seem to act on complaints, although it can happen slowly.
With SMS, in the US, it is illegal if a company is sending unwanted texts. Covered in the TCPA - Telephone Consumer Protection Act ~2015. Any legitimate provider will automatically opt you out of the campaign if you reply STOP. You can also copy the text and forward it to the number that spells SPAM (7726). They will send a bounceback and ask you what number sent the message.
It's super cludgy, but the carriers do seem to act on complaints, although it can happen slowly.