Is there a way to stop transactions from being entered through the bank feed after an account has been reconciled?

Hello tomlinosontanya71,

Glad to have you join us here. QuickBooks offers a versatile accounting platform that simplifies the way you manage your income and expenses. I'd be glad to guide you in the right direction so you can achieve your goals with QuickBooks. 

Once you connect the bank feed, the banking module will pull in transactions from the day of the connection. This means that prior transactions won't be uploaded, however, you also have the option to manually upload prior transactions as you've been doing. In case you come across duplicate transactions, you can delete duplicate transactions by selecting them in the Categorized tab in the Banking/Transactions menu. From here, click on Undo so the transactions can return to the For Review tab. You can proceed with Excluding the transactions from the For Review page so they're deleted from the account. 

Let me know if this info helps. I'll be one message away in case you have other questions.