Their module is good but buggy. If you want to raise an invoice by your own it will not generate Item Type and SAC code and the place will remain blank. Even after payment of the invoice, it wont get reflected, which is a big problem in GST. Also, the place of Supply field too won't show up. When opened a ticket with them they asked for money for debugging, never faced such unprofessional people in the commercial plugin development.
I Hope module is working fine as I can see you are still using our GST module. So hoping that its working fine.