02 April 2010
Hi Rajender singh Provision of Rule 4A and 4B say that Time limit for the issue of invoice /bill/ challan for the Taxable service is 14 days
from the date 1) completion of such taxable service or 2) recipt of any payment towards the value of such taxable service.
In your case you are liable on the recipt of payment and should issue invoice within 14 days.
04 April 2010
Service tax on receipt basis.if you received the advance against service to be provided that situation also you need to pay service tax against advance recd.so you need to pay