Ölbutikken might have some, and perhaps Kihoskh get some too sometimes? I've also bought some Cantillons at a shop called Barley Wine before, but iirc they recently closed. If you don't care about bringing bottles with you back home, just go to Himmeriget and drink Cantillons there, they've got a good selection.
Blåbær 2017 @ Himmeriget: July 4th Blåbær Lambik Vintage Tasting - Sold Out July 5th Blåbær Lambik '17 - "Release" ...No release at Ølbutikken this year per FB
So how easy/hard is it to get a bottle? My father is heading over this sunday, ratebeer also states that the shop is out of business?