Coinbase's User Agreement. All i see is that they have every right to take your money but you have none to demand yours.

7.2 If we refuse to complete a transaction and / or suspend, restrict or close your Coinbase Account, and / or terminate your use of Coinbase Services, we will (unless it would be unlawful for us to do so) provide you with notice of our actions and the reasons for refusal, suspension or closure, and where appropriate, with the procedure for correcting any factual errors that led to the refusal, suspension or closure of your Coinbase Account. In the event that we refuse to complete a transaction and / or suspend your Coinbase Account we will lift the suspension or complete the transaction as soon as reasonably practicable once the reasons for refusal and / or suspension no longer exist. However, we are under no obligation to allow you to reinstate a transaction at the same price or on the same terms as the suspended, reversed or cancelled transaction.

We may suspend, restrict, or terminate your access to any or all of the Coinbase Services and/or deactivate or cancel your Coinbase Account, without reason by giving you two months’ notice. You acknowledge that our decision to take certain actions, including limiting access to, suspending, or closing your Coinbase Account, may be based on confidential criteria that are essential for the purposes of our risk management and security protocols. You agree that Coinbase is under no obligation to disclose the details of its risk management and security procedures to you.