I have not yet received my monthly bill, but the amount has already been debited. How is this possible?

The processing of payments is fully automatic and may take a few days. If the amount has already been debited from your account and you have not yet received an invoice via Email, the billing has not been fully processed at that time.

This is resolved as follows

Once the payment is fully processed, the invoice will be automatically sent to the Email addresses provided. Additionally, you can always download all invoices yourself (retrospectively).

See Octalarm Connect: Monthly payments for further explanation.