Idiotic parking system

When I insert my ticket to pay, it is returned and says it's still valid (first 20min are free). When I reach the gate 2 minutes later I get told to make a U turn to go pay, because it has expired. So clearly the system does not extend your exit time when you attempt to pay. This means your ticket can expire 1 second after it is validated. This is an idiotic system. The attendants don't give a ****. They just have attitude and are rude..