GST refund help for IT companies which having offshore clients only

Hi, we are running a small IT company that exports services to foreign clients in countries such as the USA, UK, UAE, and Australia. As we don't have any sales in India, we are not required to pay any GST. However, we are facing a challenge when it comes to withdrawing the deposited GST that we pay to our advertisers such as Google, Facebook, and LinkedIn. They charge us 18% GST, and a significant amount of money has been stored under our GST account. Unfortunately, our auditor has not been able to withdraw the funds since the inception of our GST account. As a small business, we need that money to further invest in our business to grow it further. If anyone has any suggestions or knows of a firm/professional who has dealt with similar cases, please respond.
We are proprietorship firm not Pvt ltd company.