You can't buy/have more than one streak freeze at a time. You could only buy one, use one, buy one, use one, buy one, use one.
I bought them all one at a time! they did disappear!
What do you mean by 'all'? There's only one streak freeze.
I got three streak freezes and they all disappeared!
You cannot get three at once. You can only equip one, which will activate if you miss your practice window. It is possible that that is what happened.
It may be a glitch. Try refreshing the page that helps when it does that to me.