Entries to revenues accounts such as Service Revenues are usually:

It depends on the nature of the transactions affecting the Revenue accounts.

Generally we recognise revenue by crediting our acounts haven satisfied our performance obligation in delivery the contractual service to the client. 

However, in cases where we have returns and or disputes, as much as some companies creat an independent account (discount and or sales return), other companies directly offsets these returns on revenue against the respective revenue account as a debit

 Service revenue are credit and temporary account apper on face of Income Statement which is offsetted with expenses accounts and closed in retained .earning that considered an aliment of stock holders equity

Service Revenues are generally credited.

Its a thumb rule in accounting

Debit the expenses and credit the incomes

And since Service revenue is an income it will appear on the credit side.