Itc refund on export of service without payment of tax

Hi All, Can we claim the Refund of  ITC in case of export of service without payment of taxes unsequentially i.e can we claim the refund of September and October 2017 before claiming the refund of July 2017. In my case  the Bank Realisation Certificate of foreign currency for the month of July is not yet received but the same is available for September and October. As the realisation certificate is a mandatory attachment to the application,,Can we move forward with the refund claim in an unsequential manner.

Thanks in advance!!