no berries on my snowberry!

Hello. I bought a beautiful pink snowberry plant 2 years ago when it was covered in berries (Septemeber time I think?). Since then it hasn't 'flowered' at all. Last summer it just lost all it's leaves and looked dead. I put it in shelter over the winter months and when I took it out earlier this year it had completely replenished itself with leaves and looked very healthy. But now the same thing is happening again. It is loosing all its leaves and though there are small pink buds where it looks like a berry might appear, they are now too dying off.

I keep it in a pot which is well drained.

Any suggestions???

Many thanks. x