I'll try and help to clear up some of the things that can go wrong with shipping in and out of Europe. Also, let's leave an asterisk for the COVi skata (that's Greek for the s-word).
Anytime a package changes hands here, there may/may not be a delay. Also, if the package has not cleared customs, it may need to be by the company or the receiver. (maybe Oisin's case)
If the package is not cleared within X number of days/weeks, it'll be returned. Best to contact the office at the airport that handles customs. DHL, Fedex and all those guys have their own people that will clear customs.
This is also where the package can incur additional fees. Here they won't clear some packages until you agree to pay their fees in advance, especially if it was shipped with a business label.
If it was shipped from a business, then there will be import fees, storage fees, clearance fees, etc. If you put a phone number or email on the package, they'll contact you most times.
This is why I ship solely with the post office, I don't use business addresses or names and I always declare the items as "Gift". Is it foolproof? Nope, but the vast majority of the time it works.
Most packages mailed with the postal service hitch hike rides on commercial airlines. If there is a lockdown, strike, bad weather, etc., near the destination affecting air travel...expect delays.
Try and see if you can get a hold of an email or phone number for the customs folks handling your package. They may require you to send an invoice that matches the shipping declaration.
Hint: it helps if your PP transaction or receipt and the customs declaration amounts match.
