One of the service's terms says:

"Your free trial for the service account to be used has yet to expire, and you have yet to be charged a service fee."

You say you've been playing for about five days. I believe the free trial for a new game purchase is for one month. So it sounds like you might need to wait another 25 days or so.

You can try using the in-game support center for more help; maybe they will refund the money or something.