A British consumer advocacy group has launched a $3.8 billion antitrust class action against Apple on behalf of its 40 million U.K. customers alleging the U.S. tech giant is fleecing them by locking them into iCloud.

A consumer rights group in the U.K. has filed a lawsuit against Apple, claiming it locks its customers into the iCloud cloud storage service.

Apple encouraged its users to sign up to iCloud to store photos, videos and other data while making it difficult to use alternative providers. Customers then had to pay for the service once their data exceeded the free 5GB limit,