In case the Billing Contact does not respond, the License to Use the Domain Name is automatically cancelled. In case the Owner/Registrar wishes to re-assign after this cancellation, the renewal fee will need to be paid as well as an additional fee of €10. Please not that in case the Owner/Registrar wishes to be reassigned the domain name, this needs to be requested within a period of ten (10) working days (Annex I, article 4(j)) from the date of expiry of the domain name. In case it is not, the domain name will become available for new registration.
The procedure that needs to be followed can be found here.