Sadly, it's not that easy. If they were advertising on the card, then the ASA would take an interest. Information given down a phone isn't covered by the ASA, so it'd have to be trading standards, where all the burden is on the complainant to prove that it's impossible that the remedy being offered works. It's not enough to say that the suppliers have no evidence that it does work. So all they need to do is use a slight variant on any quackery and I'd have to fund a complete medical trial to get them to stop.