Smoothies at 7/11?

Is there a secret to get the smoothies at the 7/11?

I just went to 5 of them around takadanobaba/waseda. One didn't have a machine for smoothies, one had only the vegetables one, the rest didn't have anything left.

Is there a secret to get smoothies?

Is there a way to know which 7/11 have a smoothie machine in the first place?

Is there an collaborative app where people can tell if there are any smoothies left? (Hey let me dream alright)

I know it's silly but it's 35 degrees and I was looking forward for that blueberry smoothie……

Edit : answer from kailadanae
If you can read Japanese, the 711 Website can be used to search locations and you can check the "セブンカフェスムージー" box to limit results to locations with the smoothie machine and plug in your closest station for nearby results. I'm moving next week, and I just took the opportunity to check. Fortunately it seems that the closest 711 to me offers smoothies, which is nice since I've gotten used to them (and I get them relatively frequently at the 711 nearby my current place!)

Edit 2:
Thanks guys, just bought a blender and went to gyumo.

Just some frozen fruits, milk and sugar and I'm happy.