I’m getting charged by iTunes for subscriptions I’ve cancelled. I need to be refunded.

Double check that the subscriptions that you had through Apple are cancelled this way: https://support.apple.com/HT202039

If they are inactive and you need to request a refund, contact iTunes Support by going to https://getsupport.apple.com, selecting Billing and Subscriptions, then Subscriptions and Purchases, then Request a refund and select one of the options.