I would like to close my account

Hello guerdy,

You can't close an iTunes & App Store account. It isn't really a stand-alone component, it is all part of Apple's integrated iCloud services through your Apple ID. You can ask for your entire ID to be deleted but that's pretty serious and final as it permanently cuts you off from a lot of Apple's features, including past purchases you may wish to re-download at some stage.

You can simply stop using the store. Remove payment information from your Apple ID, though realize the same payment information is also used for App Store purchases and subscriptions.