28. In your case the Indian company is working as an agent of foreign company whose job is to facilitate the transaction in goods between foreign supplier and Indian customer. Your company is charging service charges/ commission from foreign company. The transaction value of goods is directly impacting the foreign company's bank account.
Your services will be treated as intermediary services and in case of intermediary services place of supply is "Location of supplier".
Actually in order to determine, whether the supply is Intra State supply or Inter State supply, two factors are involved and they are (1) Place of supply, (2) Location of supplier. If both are in same state then supply is 'Intra State" and if they are in different State , the supply will be 'Inter State supply'
Now come back to your case. In your case the supply is intermediary services. In Intermediary services the place of supply will always be the 'Location of supplier" (Please refer Section 13(8)(b) of IGST Act, 2017). So the both factors are 'Location of supplier' and you will charge CGST+SGST.
Your services will not be covered in "Export of Services" because the place of supply is India.