QuickBooks Online Data Corruption After Desktop Migration (Invoices & Payments)

After we migrated from QuickBooks Desktop to QuickBooks Online back in August I found some customer invoices & journal entries that were used to apply payment, were listed as open on my open invoice report, but with a zero balance. I thought they just needed to be linked again, which I did. A few months later I found our balance sheet in cash basis was out of balance. It was due to these customer payments, some going back to 2004. As per Intuit-QuickBooks troubleshooting info on how to Fix a Balance Sheet that's out of balance, I changed entry dates to the future, then changed them back. I even deleted some entries & re-entered them. The balance sheet is now accurate, but now those same customer invoices & journal entries are showing open again on my customer open invoice report. Also, some of them are now showing a balance due, instead of a zero dollar balance. The report will show an entry with one amount, but when you click into that entry, the amount is different. One good example, I have a few invoices that all had 2 line items, one in the amount of $2362.50 & one in the amount of $65.00, totaling each invoice at $2427.50. If you open the invoice it shows at the bottom a payment in the amount of $2427.50 was made, but at the top of the invoice page it shows only $65.00 was paid, with an open balance due of $2362.50. There has to be some kind of data damage, but I don't know where to begin. Some searches mention migrating our data over again, but would that do anything to our current books after 5 months now?