domain registration with different top level domain of our brand

Dear Experts

it is observed through the search engine that is google , the agents or brokers to earn the commissions have registered our brand domain with different top level domain that is our domain with TLD as .com the agents or brokers are creating the domain with TLD as .in and etc and show casing our product in their website and confusing the prospect, by reaching them and they come to us for the brokerage commissions.

1. we have many projects and every project is named with our brand and project name but one of the broker/agent has created the domains with minor change of our brand project names and as well with different top level domain as said like .in and hosting the web content of our project and with different contact number and email , he is attracting the prospect and once they reach him then he is trying to bring them to us and ask for agent commission,
Please suggest what action we can take on him also what measures to be taken to avoid such and also can we inform the search engines for example how and where to inform so that search engine will not consider them, please suggest all possible best practice to handle the present situation and how to avoid such, thanks in advance.