Brand new here, my day 1 observation.

@kbertetto welcome to the forums. Yep, SS didn't deliver and I suggest you call, tell them so and request x month of monitoring or whatever compensation you think you are due. Customer for 8 years and they have gone out of their way to make it up to you when they screw up.

Did you actually test the batteries before replacing them?  When I got my system back in Nov, half of the sensors reported low battery.  That went away eventually on its own and hasn't been back.  I think I even remember a keypad update that fixed errant low battery warnings.