Determination and billing of charges

(1) The processing of traffic data under section 9(1), first sentence by persons under a duty pursuant to section 3(2), first sentence, nos. 1 and 2, for the purpose of determining charges and billing end-users, may take place only in accordance with paragraphs 2 to 4. Where a provider of a telecommunications service provides its services over the public telecommunications network of another operator, that operator may transmit to the provider of the telecommunications service the traffic data collected for the provision of that provider's services. Where the provider of a telecommunications service has concluded a contract with a third party for the collection of charges, the provider may transmit to the third party the traffic data under section 9(1), first sentence, nos. 1 to 3 and 5 only insofar as necessary for collecting the charges and preparing an itemised invoice. The third party may process the data only for that purpose. The third party must be contractually obligated to observe the secrecy of telecommunications and the data protection duties incumbent on the provider of the telecommunications service.
(2) Persons under a duty pursuant to section 3(2), first sentence, nos. 1 and 2 must, without delay after the connection ends, ascertain from the traffic data under section 9(1), first sentence, nos. 1 to 3 and 5 the data necessary for calculating the charge. This data may be stored for up to six months after the invoice is sent. Data not necessary for billing must be deleted without delay. Where the end-user has raised objections to the amount of the connection charges invoiced before the expiry of the period under the second sentence, the data may be stored until the objections have been conclusively resolved.
(3) Insofar as necessary for the billing of the provider of a telecommunications service with other providers of telecommunications services or with their end-users, and for the billing of other providers with their end-users, the provider and persons participating under section 3(2), first sentence, nos. 1 and 2 may process the traffic data under section 9(1), first sentence, nos. 1 to 3 and 5 necessary for calculating the charge.
(4) Where the provider and persons participating under section 3(2), first sentence, nos. 1 and 2 collect by invoice charges for services of a third party rendered in connection with the provision of telecommunications services, traffic data under section 9(1), first sentence, nos. 1 to 3 and 5 may be transmitted to the third party insofar as necessary in the individual case for enforcing the third party's claims against its end-user.