The siblings are half-right; there is the ECJ, and a lot of law is harmonised, but far from everything. But it has nowhere near the political significance of the USSC. And both are appeal courts, so you have to exhaust your country's system first and be granted leave to appeal.

I don't really see there being much of a case to answer, although it may be possible to get the alleged secret law enforcement request. OVH terms of service will undoubtedly allow them to terminate your account for any reason.