Gst invoice not uploaded in august 2018 by mistake

i have made an gst invoice on August 2018 and sent it to the respective party.

the party also took itc in August 2018

but we have made a mistake by erroneously delete the bill and made another gst invoice to another party on same gst invoice no.in August 2018

now in the month of December 2018 this mistake has become evident from the party's accounts statement.

the party has already taken itc in August 2018 and we have not uploaded the same in August 2018. so.how could i rectify this mistake whether by making another gst invoice in current date or otherwise ?????

kindly solve this problem asap as both of us still at a loss ..... not knowing what to do now ...

thanks and regards,

Abhijit Hui

9804970973