ThyssenKrupp Elevator — not working of lift

Address:

Mumbai City, Maharashtra

the service person of ThyssenKrupp Elevator are not doing their work properly. they do not visit for service on their given time. one of the lift from two lift is not working. also the residents are facing problems because there are work going on in the building so the other lift is used for that n half the residents have to use the staircase.
so i wish to lodge a complaint on ThyssenKrupp Elevator.