Service tax registration

I am not able to understand the scenario properly;

1. Are you registered in both the places; i.e., in New Delhi and Gurgaon?

2. Are you performing installation activity from both the places?

3. Why do you do the installation work at Gurgaon site and bill to the Gurgaon address site. how can the same co. bill to itself; I presume their is some drafting error;

Still, if the services are used in providing the output services, the cenvat can be claimed subject to restrictions of Cenvat Credit.

Dear Sir,

We have give the Gurgaon premises on rent.

We have only one service tax registration on New Delhi office & also bill generate at Delhi office.

We have service tax paid on Gurgaon services on instalation of lift in building. 

Can we take the input with Delhi office registration which paid on Gurgaon premises services?

wainting your valuable guidance. 

Thanks & regards,

ANUJ GOEL Contact No.: +919958484182