Smoke detector/fire alarm

My SimpliSafe smoke detector/fire alarm is showing a constant yellow light and an intermittent flashing red light.  I have changed batteries twice in 7 days.  I have made sure the red plastic arm in the battery compartment is in the correct position and the battery is inserted correctly.  There is a micro switch on the bottom of the alarm unit and I am not sure if it matters how the alarm is positioned on the mount.  The system went into "chirp" mode last week.  Changed battery.  Went into "chirp" mode again this evening.  Changed battery again.  The original batteries were 12-204 alkalines.  I have been replacing them with C123A alkalines.  The chart in the store says these two batteries are interchangeable and equivalent.  True?  
Dale