I was collecting food and I clicked the expansion by accident since my phone is slow and I didn’t click on gems but the top of expansion and it bought it and I didn’t want it. It was a rly bad bad too where u can’t place much. I wasted 20gems

Try sending a ticket to support and see if they will give your gems back. It is not likely but at least you can ask. Also go into the settings and turn on the confirmation for gem purchases over 20 gems.