Thank you for reaching out!
Unfortunately, we are not able to supply spare internal components for the router.
As for the torn-off connector, would you be able to verify that the contacts are not bridged? That could cause a short circuit and could render the device unresponsive. As there are quite a few sensitive components around the power connector, could you verify that they and the middle layers of the PCB were not damaged?
Also, please make sure that the passive PoE adapter/switch that you're using can supply enough power. Modems in RUTX12 are initialized during the boot sequence, and as the RUTX12 can draw up to 22W, this may cause a voltage drop in the PSU, causing the RUTX12 to lock up.
Let me know if any more information is needed!