Govt. receipts

my client is govt contractor and he works in a pwd department. after work completion he received the amount and govt department deduct the 2% tds on it. But when i am filling 3b return which turnover i will assume for example.. gross receipts 500000. and pwd department deduct 2% tds on 500000 i.e. 10000. govt certify the amount of work 500000. my question is, i have to consider the taxable value 500000 or 500000/112*100 in gst return. becuse in govt department we have not raising bill with tax.