Great sized blueberries but no taste

I usually get the fresh blueberries, however, they were out of stock, so I decided to try these instead. The packet seemed to be quite full and it seemed that there were quite a few big blueberries in there, which I was really pleased with. However, once I had defrosted the amount that I needed, they seemed to shrink and also the taste/flavour was disappointing, they didn't taste of anything sadly. I'll stick to the fresh ones in future.