Incorrect gst 3b return file in july 2017

Kunal (NA) (32 Points)

13 November 2018  

Background: My client have 2 GST i.e. Delhi (DL) & Maharashtra (MH) and providing security service. Before GST, he was having Service Tax ragistration which later got ragistered as GST from Delhi. Client had a business in MH as well and they requested for local GST ragistration.... Hence he got GST ragistered for MH as well but late in 1st week of Septemeber. Before cut off date for July 2017, his tax consultant filed GSTR 3B for all the sales (including MH)....but later customer requested to file return MH seprately. hence, customer paid GST twice for one invoice...one under DL and other one under MH.

Kindly advise how to correct this .... September 2018...GSTR1 not filled. will file the return after knowing the answer.