I have to adjust entries from a trial balance and other information given as of December 31, 2015. Here is one of them that I do not understand.

1. Fees received in advance from clients $6,000

The answer is dr. service revenue 6000

cr. unearned revenue 6000

Why is the answer not the other way around, since it received fees in advance, shouldn't unearned revenue increase and service revenue increase??

Also what happens to the cash that was earned??