Frequent Spam / Marketing SMSs without OPT to OUT

Truworths sends frequent spam / marketing messages via SMS. These messages have no OPT OUT possibility. I do not wish to receive these messages, nor I have signed for these messages. I have contacted Truworths by email to remove me from the database only to be responded that they need my ID to remove me from the database. Based on the law I do not need to provide my identification but my name and additionally mobile number should be adequate to remove myself from this annoying constant advertising. I haven't event provided you my ID in the first place! Based on this experience I will never NEVER shop in any Truworths shops, so so much for your marketing efforts.