missed bill in may month

tazeem1922@gmail.com (37 Points)

09 August 2018  
I have a bill of may month it is neither shown in 3b nor in gstr1.
I have to submit my gstr 3b of july.
my question is how can i show this bill?
how the interest is paid on gst portal?
my next question is I left to file all bills of jan and feb in gstr1 in mar month but now i file that all bills in gstr1 in june should i pay any interest on those bills ?