How to easily fix/replace central vacuum wall mount bracket?
I would use some 5 minute epoxy to glue in two little pieces of plastic or wood.
You  may need to carefully  clean up or remove the old remaining parts of the screw hole tabs with a small hacksaw blade or an oscillating saw. Careful not to cut the wire.
Once the epoxy is set then you will need to drill the appropriate size hole for the  old or new screws. The dill bit should be as wide as the body of screw but narrower then the threads. This is so the threads will grab the wood/plastic but not split it.