I have carefully read your questions and descriptions. My views and suggestions are as follows:
First of all, if you and his company are both affiliated to a large company like Jindi, company, both of you are his agents, so there is nothing wrong with this. However, you must explain the situation and current situation to the leaders of the large company, and ask them to clearly define the scope of business and acceptance for you, so as to avoid confusion of functions in the future, which will be detrimental to both agents.
If neither of you is an agent under a large company, but works independently and operates independently. Then, it is recommended that you go to the industrial and commercial department to apply for the registered trademark "Jindi". After successful registration, other merchants cannot use your registered trademark.
I hope my answer can help you and satisfy you.