When a volume's mount path is removed from a service in the UI and deployed, the volume is deleted, not just detached. If the volume had data, a restoration link was sent to your workspace admin's email, and you have 48 hours from deletion to restore it. Please check your email (including spam) for that restoration link. For future reference, the CLI supports a proper detach operation (railway volume detach) that separates a volume from a service without deleting it, allowing you to then reattach it to another service with railway volume attach.

I am not sure how you can equate "Disconnect Volume" to "Delete Volume"!! These are 2 totally different things! I assume that disconnection of a volume leaves it open to be connected to another service. In my case, I wanted to investigate the content and file system on the volume due to which I connected the volume to a Dump service. And then I wanted to re-connect it back to the backend service. It worked the first time (disconnecting from backend and connecting to the dump service) but now the reverse is not happening! This is all from the UI. I tried to attach from the CLI as you suggested and it worked (I am verifying). No email or any other sort of warning was received during the disconnection process

I think this may be a canvas issue. Sorry about that. In the future, you can try resetting the canvas via Bottom left -> Canvas settings -> Reset canvas