Dyson V15 Battery Failed and No Replacement Available for Months

The battery of my Dyson V15 upright vacuum cleaner failed; when I called live help, I was advised to just get a new one. But no one can give any clear indication on when the spare battery would be available; it hasn't been in stock for months. It's annoying because although you could buy a complete new vacuum with a battery, there is no way to just replace the battery. This makes me disappointed, particularly in relation to a brand I thought to be consistent. Better communication and support would have been much appreciated, especially for a product of this price level, and it's causing me doubt in Dyson.