Bills foreign country but ship to India only

Yes you have to pay

As one of the major conditions in export of service is the place of supply (POS) should be outside India. But in your case the POS seems in India. So, you should have discharged CGST & SGST.

Anyways now also u can make payment of CGST & SGST and can go for refund of IGST paid earlier.

Will you please give more clarity on the service u have exported, to make confirmation about the POS???