long story short, do not make any in-app purchases. the next day you play, you get a new guest username, and start back as if you were a new account. any purchased coins and experience points you've gained are gone.
A guest account is just that and is intended for a one time use in order for you to try out the application, you should never purchase on this type of account for that very reason unless you intend to use all the coins you purchased during that visit. If this is via a mobile device, I suggest that you remove the game and re-install the application and register an actual account before you purchase coins. Thank you for your comment and patronage.
Follow IGG @Facebook.com/IGG Follow CC @Facebook.com/CastleClash