potion for dragon

how or where do you get the green potion for the dragon's headache

Go to the store on the Buildings page and buy the heartburn potion.

The potion is not in the store. I am stuck. Note: I am playing on a kindle fire.
Can someone please help me?

Before the recent update, the potion was in the store. I updated, starting over of course, reached the point where I needed the potion, went to the store and, now, it is no longer anailable. Love the game, love playing it on my Kindle Fire, am terribly disappointed and frustrated. Sorry...

I'm stuck, also. No green bottle potion to buy at the store! Has anyone tried to tell the company and ask them to fix this? I love the game, but I've done everything I can do.