Delay filling of gstr-3b - previous liability adjust with available credit

We have liability for the month of Septemebr - 2018, and had available credit for set off, but we have failed to disclosed the liability for the respective month. Now for the month of December-2018, we are disclosing the GST liability and will adjust with our GST Credit. 

Kindly guide me whether any interest and penalty is liable to pay while we will submnit the GSTR 3B for the month of December-2018.

Please guide me some one.

Regards