Meta has reaped rich financial rewards by selling user data to advertisers, but its business model has pitted the US tech giant against EU regulators over data privacy. In November, Meta launched a "pay or consent" system allowing users to withhold use of their data for ad targeting in exchange for a monthly fee -- a model already facing two challenges from privacy and consumer advocates.

Announcing the latest action, the European Consumer Organisation (BEUC) called the system "a smokescreen to obscure the real problem of massive, illegal data processing of users which goes on regardless of what users choose."

Meta dismissed the "general and unfounded accusations" regarding data use. "We strongly dispute these," a spokesperson said.