Elica — ELICA chimney

I bought an ELICA chimney an year ago it has got no complaints till now and working well.. I have asked for deep cleaning service and the service agent has done and went.. from the next day onwards it has got an issue with chimney shutter doors and it's not opening now but suction is working.. i have been registering a complaint on this since many days they had the motor for shutters doors has to be replaced but no one has come back again to resolve it .. 5 days back i again raised a complaint but no one has visited till now.. your service and response to customers is very bad dint expect this from you.. i need to raise a complaint on this with your senior manager or some higher official pls help me how to reach them and raise a complaint