Itunes

If you see ‘itunes.com/bill‘ or an unfamiliar charge on your bank, credit card, or debit statement - Does not mention purchases made under Family Sharing which might be charged to the organizer's card but will not appear under the organizer's purchase history or subscriptions. Ask family members about those or check your receipts. --> https://support.apple.com/HT201382

You do not say where you see this purchase. If you can not see it using the methods discussed in the link(s) above there is the possibility you are being scammed.

Avoid phishing emails, fake 'virus' alerts, phony support calls, and other scams - https://support.apple.com/HT204759

If they show on your iTunes account's purchase, and if you claim you didn't buy them (I assume you've already changed the account's password etc.), contact iTunes Support and see what they say : http://www.apple.com/support/itunes/ww (click on your country's flag, the country where you live, and which is therefore the country on the account ; click on Contact Support towards the top right ; click on Get Help under 'Talk To Us’)