Dodgy In-App purchases - I want a refund

This query is actually for Apple, but the website is so convoluted this is the only opportunity I have found so far to actually send a message.

I downloaded the Zombie Tower game to my ipad recently. On 23 December I received a receipt for an in-app purchase of £10.49, which I did not make. Benefit of the doubt, I thought maybe somehow one of my young daughters had managed to do it accidentally. However, I receved another invoice today for £6.99 for another in-app purchase from the same game, dated yesterday. I know I did not do it, and neither of my daughters used my ipad yesterday or today. So I know this is bogus.

Has anyone else experienced this?

Apple - I'm looking for a refund on both in-app purchases, as I did not make them - and you need to investigate the app/makers as there's something fishy going on. I will delete the app now, but will not let this go. They have taken £17.48 of my money that I did not authorise.

Can someone please get back to me as soon as possible.

Thanks,
Sean