Sonic Drive-In

We ordered our 3 drinks during the morning happy hour and we had to wait 15 minutes to reach the drive thru window when there was only 2 cars in front of us to begin with. When we got to the window, the worker took the debit card and 5 minutes later asked if we had cash because the card machine wasn't working. We told her we had two dollars and she said oh. i'll keep trying. After a little while we had to ask for our card back and left without drinks or anything. So 20 minutes to not get our drinks because the card machine was down. I understand things like this happen, but a) it happens too often at this sonic and b) the card machine being down is not our fault c) we waited 20 minutes to get nothing but bad service. Something has got to give.