Earlier quoted context omitted.
For future reference, just tell the vendor "I did not authorize this charge. Please refund me". Don't engage them further. When that call fails (or, if they don't pick up the phone in a reasonable amount of time), call your credit card company and say "I want to issue a charge back". They'll ask if you tried to work with the vendor. Answer "yes", full stop. There should be a phone number associated with the charge on…
And what if they then send you to collections? Now you’ve got bill collectors after you and your credit affected.
I’m not as clued up on consumer laws as I once was but I’m pretty sure in Europe their sign up page is actually illegal. Not just immoral but literally classed as false advertising or something similar. And even if that’s not the case, we do have protections against being tricked into signing an unclear contract and this would easily fall into that category.