Welcome to QuickBooks Community, micael-medcan-co.
Let me share some details about banking.
I checked our records and found no issues regarding the Nedbank business bank account. We need to make sure that Nedbank doesn't have ongoing system issues cause that can result in connection problems between the two systems. Check Nedbank's website to verify.
You can manually update it if you successfully linked the bank but unable to download transactions. Go to the Banking tab and select Update.