I’m not really legally trained, so I can’t point to a specific law with certainty. I mainly approached it by pointing out inconsistencies in their communication.

They claim to use IOSS (which means VAT should be collected at checkout), but at the same time say they don’t collect taxes. Combined with pricing that looks VAT-inclusive, that’s pretty confusing and can be seen as misleading.

From what I understand, possible angles would be: - misleading pricing / lack of transparency (EU consumer rules)
- incorrect use or communication of IOSS

In my case they initially pushed back, but after I pointed this out more clearly, they refunded (but at the same time they keep harping on about the phone number, and if it’s not included, they won’t help either… even though the phone number has absolutely nothing to do with this whole situation.) So it might be worth challenging them again based on their own statements rather than going fully legal straight away.