Got threatened by the company for complaining against poor service

Hi,

Please consider the matter seriously. Lately I have purchased a Data Card from MTS, a services company (from Russia, which is providing internet services in India). My data card was dead from September 25, 2014 and I have raised a complaint for the same in the company. But they have not responded to it and mentioned it as signal issue. After telling them repeatedly the same thing, they told me they will send someone from their company for replacement of the data card as this is in warranty.

But they did the opposite. They have called me and threatened me that pay your bill, else we know the way how to get our bill paid.

If I have not taken the service (as my card is dead), why should I pay them?

Please help.