Give them a "three strikes and you're out" - with the "out" being striking off the company and it's officers, and compulsory winding up of the company, and with the company plus those on whose behalf it sent the offending texts being jointly liable for compensation to the unwilling recipients. And apply the same to direct mail companies using the post.
Oh and come up with standard "opt in" language: "I agree to receive marketing texts from .....", and ensure customers do not have to pay anything for sending that or sending opt-outs, with separate opt-in using different language for anything that might involve a cost. Per promoter, not per sending company/agency.
Biting the hand that feeds IT
