Hey guys, Seb here from Upmind. Just giving this a reply here to say we acknowledge the feedback. Our stage at Upmind is that we're building out functionality and lots of it behind the scenes which is super foundational, but frustratingly (for us and for our users) sometimes doesn't translate into how things work on the frontend.
The biggest win we could have in terms of what seems like bugs (like immutability/deleting invoices/changing things, and also the way things look and feel confusing) is for us to basically spend a couple of months simplifying things from a usability perspective. We'd love to do that so much, but at the same time if we do that we shoot ourselves in the foot long-term.
We're probably another six months of 'beta' before some of these foundational things start rapidly translating into real-life functionality and we can then really start focusing on making things straightforward.