Landmark Insurance Brokers / Policyboss.com — irresponsible brokers

I bought an insurance from landmark insurance for my four wheeler in july 2018. I was offered a price and i have paid the same throught the online portal. One month later, i get a message saying the insurance has been cancelled because of wrong declaration of ncb which is mistake of the agent selling the insurance. I was told i would be receiving a new insurance because of the mistake. I have been trying to chase these people since then but of no use. There is no proper response. Everytime i call them, i wait atleast for 10 mins latter to be disconnected by the call centre agent.