From my Cablecom bill

"You will receive an invoice every month - except if the billing amount is below CHF 50,If the total amount of your monthly costs is below CHF 50.- we will not send you a bill, in order to save the environment. You will receive your next bill as soon as the total amount is above CHF 50.- or after 4 months at the latest."

Just pay by direct debit each month and voila, problem solved anyway.