• Exports of service with payment of tax - ground of refund claim

Hi ,
I received LUT in October 2017. I am a Service Exporter - Importer.
before getting LUT -  July + August + September => These 3 months 

1> I paid  IGST on  export.
2> I paid RCM TAX on Import .

I am planning to file  	 RFD01A	  this month for  getting refund -tax paid on Export.
Next month  I will file refund application for getting refund - accumulated ITC .

 in GSTR-3B of above 3 months   I have claimed RCM TAX amount  as  Eligible ITC  in same month
 and utilize that RCM TAX amount in same month  for paying IGST on export

 
 For example @18%:  in month of JULY-	 Data is following:
 
 export value = 200 INR ; IGST payable     = 36    
 Import value = 100 INR ; IGST RCM payable = 18  
 
 Total IGST payable = 36+18 = 54 INR
 
 1>     I paid 18 INR  as RCM and claimed it as  Eligible ITC  = 18    INR
 2>     I paid   ( 36 - 18 ) = 18  INR for tax on export .
 
 Paid through  credit  = 18 
 Paid through  cash    = 36 
 
 
 Now while I am filing  RFD01-A  for getting refund  - IGST paid on Export
 
 which amount should I claim -  36 or 18 ?
 
IGST payable  on export    = 36  
But I utilize credit 18 from RCM  and paid only  36-18 = 18 INR for export !

I am  thinking to  write  18 .	 and  will claim ITC amount  18  separately.

but when I see  “CREDIT LEDGER “ balance , I see for JULY   ITC = 0   INR
because I have utilized it for making tax payment for outward supply / export.

so If  I write  18 in   RFD01-A  ( refund -Tax paid on export )    .. I will lose 18 INR because ITC showing 0  hence  I won’t be able to claim under ITC in future.

And if  I write  36  it will be wrong ; though    IGST payable  on export    = 36   but I only paid 18 INR   for  export.   Remaining 18 INR  I paid through credit .

Please help.
Thanks