When we are making a payment for services which include service tax, Then entry will be

1. Paid to Port trust for haulage, tipping, sidding etc charges including Service Tax

Party A/c ( Port Services) Dr. 100000

Service tax Credit A/c Dr. 12360

To Bank A/c 12360

2.When making any payment of service tax after availing Servcie Tax Credit

Service Tax A/c Dr. 15000

To Service tax Credit a/c 12360

To Bank A/c 2640

3.When we receive refund

Bank A/c Dr. 12360

To Srevice Tax Credit A/c 12360