A320 Captain reported the aircraft rolled forward after brake release when push crew failed to communicate and follow procedures for disconnect. Captain applied brakes to avoid hitting the tug.

Narrative

During push from gate X; everything was routine until tug driver said he wanted to disconnect the tug and reconnect it with the tug facing the same direction as the plane. Driver said he wanted to pull the aircraft forward a little to complete the push. Driver asked me to set the brake and so I did. I then watched the tug disconnect turn around and back toward the plane with its rear now facing the nose to be reconnected. However; as the driver was now on the opposite end of the nose we were no longer in comms with the driver. After a minute or so a new voice came on the headset and excitedly asked me to 'release the brake!' so I released the brake; but when I did the plane lurched a little indicating that they must have been attempting to pull the aircraft with the brake set. After a min or so I was monitoring something in the cockpit awaiting the 'set brake' command when FO (First Officer) states 'I think we have been disconnected' . I looked up to see plane creeping toward tug which was still in proximity to the nose. I stepped on brake and saved plane from contacting tug. I saw one ground crew reprimanding another although it was not the tug driver who was reprimanding. I felt this push crew was completely disorganized and without a designated leader. We never got a 'set brake' command and I was never able to give permission to disconnect. Although they did show me the pin as they walked away. This push crew was doing their own procedures unlike I have ever seen after decades at my company.If it had not been for FO noticing that plane was creeping and alerting me we may have contacted the tug.