Armed system... zero alerts/notifications rec'd/came home to alarm OFF!

I armed my system before leaving town. I have every single notification activated both for the app and for text notifications. I received NONE while I was out of town. When I came home today I entered and noticed the alarm wasn't beeping (Entry delay waiting on code) and when I looked At the keypad it said it was OFF!!! I immediately went to my app and it said it was armed. My system is the older system however all the batteries were new when I got the system in June... the power went out briefly here but definitely not for 8 hrs! I checked with neighbors and they said it went out and came back on. I never got a power outage notification and SS customer service showed nothing on their end and showed my system still in armed status (as I was sitting on my couch)...

They are sending me rechargeable batteries for the base but I'm perplexed and concerned that I received no power outage notification and my alarm was off even though on my app and at SS it showed on. It has removed any peace of mind for me. I need to know the system works... and that when I'm out of town and the app says it's armed that it is indeed armed. Any suggestions???