I just bought the game so im unsure if this is a known issue or not but when I was ingame just doing the first real level
I on accident clicked twice when I was building so it bought it twice on the same thing even though I only got it once
heres a imgur of it: imgur.com/0X8c9lg
sorry about the second screen I couldnt be asked to go in my settings to turn it off >.< hope this helps