ITC of GST paid on electricity, telephone etc

Many suppliers do not claim ITC of GST paid on services like Electricity Board, Telephone companies incl. BSNL, all the BANKS on service charges etc.

Some have doubt that we have not informed them our GST tin and it is not reflected in their bill/invoices.

There is some confusion in the minds of small and medium traders etc. in this respect.  

Can any body or expert provide the factual position of this aspect and guide how to claim GST paid on such items.