Again: none of the troubleshooting you performed previously is worth reconsidering or analyzing.
The OBi 200 uses only the center two pins of its phone jack. If you think you have damaged it, use a flashlight and a magnifying glass to look at the jack and make sure the pins are not bent. The fact that the OBi now works with a corded phone proves that the jack in the OBi is connecting properly to the plug on the phone cord.
Regardless of how long your wiring guy has been doing that job, here is what you need to understand:
When a building has an old-school POTS telephone line in use for a security alarm panel, it is wired like this:
The telephone company supplies telephone service coming into the premises on a two-conductor pair of wires (known as tip and ring). Those two wires are then routed to a special phone jack, called a RJ-31X exclusion jack. This jack loops the telephone line connection through the alarm panel's "communicator" via a relay. Normally, the relay is closed, and the telephone wiring loops back from the communicator to the RJ-31 jack, and then out to the pair of wires supplying all the other jacks in the house.
When an alarm is triggered (or tested), the relay opens, which cuts off the loop going back to the jack's house wiring pins (center two), so that only the alarm panel's communicator is connected to the telco. This is called "seizing" the line. It prevents bad guys from picking up a phone to interrupt the call to the alarm monitoring station.
The RJ-31X jack also has a pair of spring-loaded gold pins inside that open up when a plug is inserted into the jack. This removes the direct connection to the rest of the house, and loops it through the panel. When you unplug the alarm panel's modular phone plug from that jack, the spring-loaded pins make connection inside the jack, thus looping it directly to the house wiring, and disconnecting the alarm panel.
So: if, and only if, the alarm wiring person correctly wired it this way, all you need to do is to unplug the phone plug going to the RJ-31X, and the rest of the house wiring is now connected to the telco.
IF you want to use your OBi with the house wiring, you must remove the wires coming into the premises from the telephone company (or cable company if they supply your telephone service). THEN you can plug the OBi into any working wall jack using a standard telephone cord. Again, if, and only if, the wiring is done properly, then every jack will now carry the OBi's dial tone over the center two pins of each jack.
If this does not work, I will not troubleshoot it for you via this discussion, nor will I answer any further questions. It's pretty clear that you are not qualified to mess with the wiring on your own. You will need to hire your wiring person to do that.