Annoying if the amount charged doesn't seem right. Sometimes there's a logical explanation (for example a separate extra charge alongside your subscription), but it may also be a mistake. We're happy to look into it for you.
Contact us and tell us which charge(s) it concerns. If we've charged too much, we'll correct it: you'll receive a credit note and the overpaid amount will be refunded to your account. That way you never pay more than you should.