If ya quit then why care about it. Walk in and tell them what you really think, demand your check in your most asshole tone. If its a public place be a real dick, if its a fast food resturant order an item and demand they dont flick boogers in it like they normally do ect. Take advantage of the chance to bea real prick and savor the moment.
When I was young or back in my teens I faced this a few times and well, it depends on the terms you left on. If you left on good terms, don't cause a scene or be rude cause you might need them in the future for a reference. If not or either way I have found in one experience I phoned the Manager and asked for them to send me my last check in the mail. This way if they agree, just say thank you and hang up the telephone. Or- sort of dress incognito and wait until the place is really busy and then go in and ask, as the busier that they are the less time they have to discuss anything. Also if all else fails, take backup, like grandma, a parent, or someone to lean on. Brings back awkward flashbacks of picking up that last check or phoning for it.
Dont be such a pussy, what can they do take away your fucking birthday?? If they open thier mouth just tell them to shut the fuck up and hand over the cash they owed you, your no longer obligated to listen to the fucking douche!