Alarm switched itself off - any ideas

Hiya

Anyone had this or can provide any ideas. SS3

I was sitting in room where my base station is.

Alarm deactivated 3 hours before using key fob.

Three hours later as I was sitting here it then played the tune it plays when it first starts up then said "welcome to simplisafe"...

I jumped up and noticed on my phone it then said "alarm disarmed".

I looked at keypad.. it said "OFF".

I called simplisafe and they said they would look into it but it showed the alarm had been disarmed by phone app using cellular.

I am inside the house, on wifi and did not do this.  My wife is also in house on wifi and did not do this.  Also the basestation did not say "alarm off" it played the tune and said "welcome to simplisafe".

Either way - my alarm was deactivated.