Hindustan Petroleum Corporation [HPCL] — overcharging for replacement of regulator

I was give a regulator which cost rs 150 with a new cylinder from hp indu gas service, the regulator turns out to be faulty and when i took it for replacement they are asking rs 250 out of thin air.
I don't know how come replacement cost be more than the cost of the product.
When i enquired they said it is the replacement plus penalty charges. The hpcl website clearly mentions that a normal tear and wear regulator will be replaced free of cost whereas a damaged one at normal tariff. But they are asking more money even when the fault was in their product which showcased upon first use itself.
This is highly unprofessional and consumer harassment.