#3: On invoices with refunds after importation via the WHMCS importer (causing overdue invoices in Blesta) : It's more involved and largely is related to our WHMCS customer's final invoices or SLA credits given over the years. If a refund is given to a customer on an invoice, and the invoice is marked paid/voided, WHMCS considers the paid or voided invoice as closed. Even though there is a technically a balance.
While this does require manual correction, the manual correction isn't needed on Blesta... The correction should occur on WHMCS.
After adding a line item to the WHMCS to reflect the refund to the customer, Blesta is happy.
- The issue with the importer not applying multiple payments on a WHMCS invoice was related to credits which was also resolved by adding line items to subtract money owed on the invoices and removing the WHMCS credits. WHMCS credits being applied to invoice creates a transaction that is visible at the bottom, but the invoice itself is never marked while a line item reflecting the credit. WHMCS just has the transaction and marks the invoice paid. Blesta appears to want an actual line item.
All of issue #3 can largely be attributed to the sloppy accounting that is allowed by WHMCS. While it all "just works" it's by no means clean accounting.
In summary, my original list is largely resolved and I hope my posts help someone in the future.