My question involves criminal law for the state of: Washington

I am 21 and was stupid enough to try to shoplift from a micheal's. It was a $6 tanktop, the cops were not called. They said I would get something in the mail to tell me how much I owe them...

I was caught last thursday, it's only Monday but how long should I wait for it to show up in the mail before I call someone?

This is the first time I have been in trouble with anyone other than my parents so I am extremely stressed and nervous.