According to the European Commission, a pledge by Google not to use Fitbit’s data for advertising in a bid to address competition concerns was insufficient.

Google announced its Fitbit acquisition back in November, and it could be a full year or more before the company is able to finalize it.

The company aims to take on market leader Apple and Samsung in the fitness-tracking and smart-watch markets via the deal.

Google has promised not to use data but regulators and consumer advocacy groups have been raising concerns about the search giant gaining access to sensitive data like fitness activities, heart rates, sleep patterns, and more.

Consumer groups from across Europe, the US, Mexico, Canada, and Brazil have already called the deal a “test case” for regulators’ abilities to prevent data monopolies.

EU officials are reportedly demanding more concessions that would guarantee that Fitbit’s data won’t be open to third-party developers. They also seek assurances that Google won’t use Fitbit data to improve its search engine.