Blackberry Woes

Blackberry bush has finally decided to fruit this year, lots of large ripe fruit on it.
I went out to pick some last week but found that the ripe/black blackberries would not come free of the plant, so I thought they would need another day or two to completely ripen even though they looked right. Tried again a few days later and they had gone mouldy....

What am I doing wrong?

Ahh, thanks. I had a few squish in my hands which is why I thought they might need longer. I reckon I left them on too long then as they would need to be a bit firmer to pull off. Gotcha!!

Cheers