Liftmaster Gate Staying Open

We had an LA400 liftmaster controller put on our front gate. The door stays open and has an audible 3-beeps when sending a command via remote or keypad.  We had this issue before and called a liftmaster contractor. He stated the batteries were low after discovering the breaker had been tripped, so the gate was no longer receiving electrical power and was running off the batteries. We had those changed out and flipped the breaker back on.  Fast forward 4 weeks later, same thing occurring except this time the breaker is still on.  It is like power is not getting to the gate, and it is running off batteries.  My question is does this sound like an electrical concern because I do not want to call the liftmaster (not electricians) contractors again.  The person who installed it needless to say is a ghost and cannot be found.  I am at wit's end with this.  I just want the right person to be able to look at it, troubleshoot it and repair what is going on, which seems to be electrical.  If it is electrical, we need an expert who is familiar with the gate installations so they know how to troubleshoot, right?  Any recommendations in the Atlanta area would be greatly appreciated.