odds are it's fake information, and the person behind it is in China.

You can avoid it, block all advertisements on your phone/computer, and don't click on clickbait.

Well, that is Switzerland, not Italy... (You said Tekka, not Tekka Date initially, too... they're different companies, though almost certainly under the same umbrella of the same fraudulent group of people.) But it makes little difference. Although Switzerland is not a member of the EU, and generally a kind of rogue state (pretty much all fraudulent activity in Germany that doesn't come from Romania or Russia comes from Switzerland), the relevant rules still apply. Even though the right of revocation as such is generally optional in Switzerland (other than in the EU), for that to be the case the merchant must explicitly tell you that you do not have that right before you agree to a service. From your description, that didn't happen, and you were not even explicitly informed that an agreement was to be made. So... exact same situation. No binding contract, no base for claims against you, and any claims made are therefore fraudulent a case for the police. You will likely get mail from a money collector if you don't pay. Ignore that. If they keep charging your credit card, charge back and report every incident to the police (note that charging back costs the other guy some real money!). If you still don't pay, the money collector will come up with a diversity of threats (both legal and physical). Tell them "no", and otherwise ignore them. In the unlikely case that they go for an enforcement order, you need to object to both the order and its execution (because an order can be executed even if it is not legitimate). Best thing to do is to let your lawyer do that. Otherwise, just ignore them. If you investigate, you will find that the demands either comes from a private address in Switzerland where you are told that nobody ever heard about Tekka, or from a lawyer's letterbox who will deny knowing anything (sometimes they will point you to another company in Gibraltar, which is run by another lawyer). None of that is a problem as long as you are not stupid enough to pay. If you pay, you never see your money again. Also, above all, avoid calling them terrorists (or anything the like) or saying things like you want to kill them, since you are placing yourself outside the law doing so. Say as little as possible, this is always a good advice. The more you say, the more it becomes likely that you say something that can be turned against you one way or the other, and you do not gain anything from discussing with these people. They do this for a living, believe me that they are better at it than you. The single best thing you can do is report anything illegal to the police (and let them trace the perpetrators over 3 countries), and turn down / ignore all claims.

Please stop calling them terrorists -- that term has a specific meaning and you have no evidence what-so-ever that it applies -- based on the available information they would seem to be criminals at worst.

Let he without sin cast the first stone. My stone is right behind the moon right now go look and you will see it

I have no idea why you think this is might be a productive way to deal with this issue.