By oversight tax paid in cess instead of sgst

While making the payment for GSTR-3B returns for the month of October, by oversight we put the amount of 9 lakhs in CESS column instead of SGST column and made the payment.  We came to know that we made a mistake when we were setting off the Input and Output.  There is no option of adjusting the Cess amount with any of other tax and there is no online refund option also.  The total amount is blocked and we forced to make another 9 lakhs payment to file the 3B return.  Kindly suggest me to get back the amount at the earliest.