(d) request development and processing costs; and (e) other such necessary terms and conditions required to effect infrastructure sharing. Within 20 calendar days of the receipt of the quotation, or such other time period as agreed between the parties, the infrastructure seeker and infrastructure provider shall undertake good faith negotiations to resolve any outstanding matters for purposes of producing an infrastructure sharing agreement. An agreement between the infrastructure provider and the infrastructure seeker shall be concluded within 30 calendar days of the commencement of negotiations or such other time period as they have agreed. At any stage of negotiations, either party may declare a dispute and refer the matter to the Authority, which will support a dispute resolution process. 7.3. Coming into Force of Guidelines 7.3.1 With the effective date of these Guidelines and the Reference Contract, all provisions of these Guidelines will come into force. 7.3.2 For currently existing infrastructure-sharing agreements, there will be no retro-active adjustment of prices paid for infrastructure shared before the effective date of these Guidelines. 7.3.3 If an existing infrastructure-sharing agreement covers a period beyond the effective date of these Guidelines and the Reference Contract, already paid fees should be adjusted to the maximum prices of the approved Reference Contract as of the effective date of these Guidelines. This adjustment could either be done through a re-imbursement or through offsetting the difference against invoices of future infrastructure-sharing agreements. 7.4. Procedure in case of non-payment of invoices In case of non-payment of an infrastructure-sharing invoice, the following procedures shall be applied: 7.4.1 In case of a first-time agreement on infrastructure-sharing, access to the infrastructure will only be granted after full payment of the initial invoice has been received. 12