I have 1x Gen2 camera and 3x Gen1 cameras.
My Gen1's are working fine (except one Gen1 camera; it doesn't record on motion triggers, but live steaming works -go figure), but my Gen2 behaves like yours. According to the config page for the Gen2, the last time it was online was June 26th as well. It only shows offline and has the play button with the line through it. When I power it off then on the blue light stays on for about 5min and then the camera turns off. I seem to be able to set the wifi password to the camera, but that's it. I signed up for a new account for testing and tried to pair the Gen2 camera, it sees the camera as a new device, but then gives an error before adding the camera to the account. I guess there is something in Ooma's service that prevents 2 cameras from being attached to 2 accounts (it would make sense to have this failsafe). If I could somehow get the camera out of pairing mode or force remove the camera from my account, I believe I could get it reconnected again.
Have you had any luck getting support from Ooma?