Montjuïc Cable Car

The weather just started a little rainy powder, not much people, queue only one queue, see doing on-site buy tickets, thought already have QR code in hand, who did not know a walk through the ticket window, the staff immediately instructed to queue up to change tickets, originally thought to stop in place to wait, but the staff said we did not queue, to walk back to the end of the queue. Angry, unclear instructions, and no where to redeem tickets. I have no choice but to line up from the beginning!