Stop issuing tickets 45 min before departure

Hi

I stayed in Korea for some time on my travels, and booked a ticket to Beijing, china via Priceline.com on china southern airlines.
I have arrived to Gimpo airport in seoul 25 min before departure time doe to some problem that accrued on the way.
When I arrived they told me that they can't issue my ticket because I am to late! (That was about 25 min prior to departure) and I had to try and convince them to issue it immediately otherwise I would miss my flght.
She wouldn't do it and I had to wait for nothing till the plane departed.
I think I should get a free ticket because that just didn't make any sense, I have arrived (a little late I know but i didn't see that kind of service any other place in the world)
What can I do now?