Our main bank account not updating, seems it has been deleted by "system administrator" in log, who is this and why? how do we activate it?

I can help you reconnect your bank account to QuickBooks, bobtowsey.

Editing a transaction that affects other linked transactions, scheduled activities such as automatic updates in your bank feeds, and connected third-party apps modifying existing data are several reasons you might see changes posted in the system's Audit Log as System Administration. 

When a bank account is disconnected, the system stops the transaction from being downloaded to your bank feeds. Still, transactions added to the register will stay be active and remain as is. You can reconnect it so it'll continue to download new transactions. 

Let me show you how: 

1. Go to the Accounting menu and select Chart of Accounts.
2. Look for the bank's register and click the drop-down arrow under the ACTION column.
3. Select Connect bank.
4. Enter your credentials and follow the onscreen instructions. 

When you look into your chart of accounts you'll see a two-way arrow that indicates that it's connected. Once you've successfully connected the account, it downloads past transactions that might have already been added to your register. You can exclude them to avoid duplicates. 

Let me know if there's anything else that you need help with. Take care and have a great day!