Thanks for reaching out. Having your books accurate is essential for the running of your business. I'll be happy to help you sort out your deleted transaction and your bank balance.
Once you delete a transaction in QuickBooks Online, there's no way to reverse it. However, you can refer to the Audit log to recover the details of the deleted transaction so you can re-enter it.
Here's how to use the Audit log to locate and re-enter deleted transaction(s):
Select Settings ⚙️.
Select Audit Log.
From the Filter ▼ drop-down menu, check off Transactions and choose Deleted/Voided Transactions from the Show drop-down
Select Apply.
Locate the deleted transaction.
Under the History column, select View.
Click on the drop-right menu and all the information needed for the transaction can be found under the Event column.
Using the information from the Audit log, you can re-enter the transaction with its original transaction date.