I have what looks like a 1f78-144 thermostat. Yesterday it was set to cool at 73 and the room temperature was also set at 73. The low battery notice came on but the indicators came back on showing 73 &73. I changed the 2 aa batteries but the indicators have both been stuck at 73 even though the temperature cooled into the 60s last night with the windows open and the air conditioner turned off manually. Today I have to operate the air conditioner manually and both indicators are stuck at 73. What can I do?