Airtel - Network issue with Airtel Doongle connection 8811033386

I am facing severe network problem in my Airtel Doongle No ********** for the last few months. I have made numerous complains but there is no help. The customer care people are of no help and they just say that they are escalating the complain and forwarding the same to the concerned team. The Airtel store people in Zoo Road are useless and only knows how to sell products. A service engineer visited but he is also of no help. Everyone says a different story and try to blame each other. The service engineer says there is no problem in network, the customer care people says there is network issue of Airtel. The connection is so slow that it is not possible to do anything. Often pages dont opens . I have incurred heavy financial loss in online share trading and air ticket booking due to this regular network issue.