[FOSDEM Treasure] missing t-shirt / can't track the parcel

Hey, I'm waiting for the t-shirt to be delivered and when using the tracking link I can't see where it is: from what I understand, its state is simply "Shipment received by PostNL" - its expected delivery date was 7-9 February, which is today. My tracking ID is 3SLQKK6253319 <https://postnl.nl/tracktrace/?B=3SLQKK6253319&P=28008&D=ES&T=C&L=NL> - I received this email 7 days ago, and its details were never updated. I have no clue how to inquire about its state, nor how to complain. Can you do anything about this matter ? Thanks in advance, Miguel