Hi Isma,
Thanks for the clarification on how to disable the automatic cancellation of invoices, I've set that in my system now, so hopefully it won't happen again.
As for the invoice issue, I guess that's going to generate a new invoice though unfortunately. The problem with that, is the client has already received the previous invoice and made a payment against it, so I can't really send them another one. I'm not an accounting expert so I'll have a Google to see if there's an accounting practice which handles such a scenario, otherwise I'll have to fudge it, keep notes and hope for the best!
One thing that I did find from having a Google around was that it appears voiding a credit note is a valid thing within accounting as Sage and Xero seem to allow for it. Obviously Upmind isn't strictly accounting software so undoubtedly has other priorities. However, with the accounting aspect underpinning the system somewhat, perhaps one day it might allow for the voiding of a raised credit note, which in turn could change the invoice's status from cancelled to unpaid again, or something like that!
Thanks again for your assistance!