Are you sure that there is no transaction hash provided? Because if you didn't see one, it just means that your transaction hasn't been initiated or broadcasted yet.
In this case, the one who can help you is coinbase itself as this problem lies on their side. You can check the status of CB here:
https://status.coinbase.com.
Currently, It is said that there's a minor service outage and a few days ago, they undergone some maintenance so there's a possibility that it might be related to that.
What you can do now is to actively contact their support. It's known for its slow response so you should often bump your problem [
Everyday is recommended] as they are receiving tons of inquiries everyday.
Submit a request here:
https://support.coinbase.com/customer/portal/emails/newFacebook:
https://www.facebook.com/CoinbaseTwitter:
https://twitter.com/coinbase