Fuel flap not opening

Hi all

2 days ago i noticed that i cant open fuel flap (fuel door) on my Skoda Superb 3V L&K 190bhp as i wanted to top up add blue. Today i was playing with flap for around 1hour and it opened, however it looks like one pin which should twist and release flap when is pushed and lock and unlock  is not working. Did you face similar issue on you Superbs if yes , how did you fix it. Do you have some photos to help to see process of dismantling fuel filler flap as if i need to order new part it would help to see how to take it of and put new one as i cant see any screws to release filler plastic. Please see photo attached i am looking for something similar with add blue.

Thank you guys

Laco