Same problem here. I've sent an email to them several days ago but nobody replyed back. It has issues that prevents me from generating invoices and it says that is not supported by Shopify. If the developer sees this, contact me please.

Doesn't work for me, can't generate invoices it always says that the business i'm trying to connect to isn't available for my user

Not working at all. no support available. no way to connect it. useless app. 5,99$ for nothing. disappointing

I used this app for generating invoices It is very good for new users to set up. Very good app, 100% recommend for new sellers.

I used this app to help me generate smartbill invoices on the fly. I really like how it saves my time a lot. It would be better if you create similar apps for other services

I used this app to help me to generate smartbill invoices on the fly. I really like how it works and save my time. Thank you