I signed up for google cloud and recieved 300$ free trial. Recently I wasn't able to ssh into my instance. So I checked the google cloud console and found a message showing you must Enable billing to use further. Now I can't associate my project with the free trial account which has 285$ and 45 days remaining.[Also the number of days left has drastically reduced from 55 to 45 after this]. When I look into the free account it shows closed.
The free trial account was suspended. Reason - "Unfortunately, we were unable to verify billing instrument ownership using the documents you submitted" says Google.
Solution
Go to: https://support.google.com/payments/contact/verify
Submit Government-issued identification and proof of ownership of billing instrument. The verfication process typically takes less than 24 hours, but, in rare cases, may take a few days
For issues like this it's best to contact Google Cloud Support directly. All projects have free access to Billing Support. During the free trial, you can also access technical support using the Free Trial Troubleshooter.
For more info see also 'Get support' and 'Support during the free trial'.