You can also request a billing adjustment by writing to  servizioclienti.gruppocap@legalmail.it or assistenza.clienti@gruppocap.it

Or by ordinary mail to the address CAP Holding Spa - Billing Office, via Rimini 34/36, 20142 Milan, by calling the customer assistance service at the toll-free number 800 428 428, and also at the customer counter.