Hi there, @NextGenBizSolutions. I'm here to help you fix the discrepancy in your client's reconciliation.

To get started, let's make sure that the transactions recorded or added in QuickBooks Online (QBO) matches the client's bank statements. If there are unwanted entries, then you can exclude or remove them from QuickBooks. 

On the other hand, I also recommend checking the account's opening balance. It needs to match the balance of the real-life bank account for the day you decided to start tracking transactions in QuickBooks. Once settled, proceed with your reconciliation.

1. Sign in to QuickBooks.
2. Go to the Gear icon, then click Reconcile. If you're reconciling for the very first time, select Get started to continue.
3. From the Account ▼ dropdown, select the account you want to reconcile. Make sure it's the same one on your statement.
4. Review the Beginning balance. Make sure the beginning balance in QuickBooks matches the one on your statement. Here's what to do if they don't match.
5. Enter the Ending balance and Ending date on your statement. Some banks call the ending balance a "new balance" or a "closing balance".
6. If you see it, review the Last statement ending date. This is the end date of your last reconciliation. Your current bank statement should start the day after.
7. When you're ready to start, select Start reconciling.

In case you encounter issues after the process, use this link as your reference to fix the issue: Fix issues at the end of a reconciliation in QuickBooks Online.

If you have any other follow-up questions about reconciliation, let me know by adding a comment below. I'm more than happy to help. Keep safe!