Arrived to the customers location and greeted them inside their office space. Spoke with the gentleman at the front desk who filled me in on everything he knew that was going on and showed me the locations of the units. Customer states we are the fourth company to look at this issue. The last company out found all the VAVs turned off and was able to turn on but wasn’t able to complete anything further. After speaking with service manager determined the VAVs need to be logged into the software program to allow all VAVs to work properly for maintaining the heating of the office in conjunction with the rooftop equipment. Spoke with office manager of champion title explaining the current situation.