DirectAxis SMS Spam

I have never used Direct Axis or given them my details, yet I receive sms adverts from them sometimes several times per day! And there is no way to opt out of these messages! If you visit their website, they insist on your ID number and email address in order to opt out. Why would I want to give this company my email address (I would probably start receiving email spam too) let alone my ID number???? I feel they are completely ********* in business and are also invading my privacy. I have no idea how they got my details. And I don't feel that I should be wasting my phone bill trying to call them to opt out of something that I never opted into in the first place! However, seeing as so many people are receiving spam from them, I call on them to step up and at least give people an easy option of opting out of receiving smses! If you are going to spam people, at least try and do it as ethically as possible! Please... NO MORE smses!!