GST amount Excess paid in 18-19 Can Adjusted Now in 3B of Oct 2019

We are doing Government Contracts While Filing Late Year 3B 2018 - 2019 We have filed the contract Income Excluding GST ( 1,00,000 - GST - 12000 = 112000 ) but the department now refuse to give the  GST Amount and they said the contract amount is Including GST ( 89286 - GST - 10714 = 100000) as like department said i have paid GST For Excess of Turnover Rs. 98,00,000 GST - Rs, 1187580/-  can i adjust the amount in correct month October 2019 3B return  I have received the Cheque Of Ts.75,00,000/- including GST Bill in 3B of october 2019 and i have show GSTR -1 last year in cash i have amended in October GSTR - 1 the differ amount in 18-19 

kindly tell me i can adjust the amount in Current 3b or i want to claim only refund for 2018 - 2019 after filing annual return only and Current year i want to pay the tax for the cheque received in Oct 2019 or i can adjust with the payment excess

I.e..

18-19 - Total Turnover Rs. 2,68,00,000/-  Including GST  (23928571+ 2871429 = 2,68,00,000 ) But we Filed in 3b & GSTR - 1 as (26800000+3216000 = 30016000)

Now Excess Paid in 18 - 19 - 26800000-23928571 = 2871429  GST Tax = ( 3216000-2871429 = 344571 )

Now in Oct 2019 received Cheque Rs. 7500000 ( 6696429 - GST - 803571 ) I can adjust the amount 344571 in Oct 2019 returns that is Oct 6696429 - Less 18 - 19 Excess - 2871429 in Oct 3B Turnover as 3825000 - and i can pay the balance tax 

or i should file the GSTR 9 & 9C and claim only for refund not adjustment after financial year 

i want to show only 6696429 in oct 2019 i pay the tax as usual 

kindly do the needfull