Getting over charged for items I purchase and getting charged for games that are free

Okay so the other day I decided to download clash of clans again and begin my grind but as I downloaded the game it charged me upwards of 21+ dollars and I have no idea why it would charge me for a game that is free on the App Store now fast forward to a few days later that being this morning I bought a pack this morning that being the futuristic pack that makes your base look like it’s from the future this pac it 6.99$ usd but as I made the purchase instead of it pulling out a transaction of 6.99 or what ever one would assume the tax would be it pulled out almost 17 dollars and less then a few moments later after logging back in I no longer own this pack and cannot use it now this isn’t the first time this has happened I’m just wondering if this has happened to anyone else and how I should handle this situation