Applicability of excise act or sevice tax?

Excise duty will be applicable on manufacturing of goods and service tax will be applicable on service. I think your activity is a service.

To

Mr. Arun Kumar Singh

Dear Sir 

company has already took a central excise registration number.so how can be this process clasify under service tax. please clarify and suggest me where i can read this service and prepare my reply to the company.

thanks and regards