What to do when I got an email that the customer's bank returned a check.How do I know which client this is?

I can help you handle bounced checks received from your customer's bank, infinitypool.

When managing customer payments, one of the most common reasons why these checks bounce back is because of incorrect bank account information, which can cause payments to be rejected or sent to the wrong account. Also, the insufficiency of funds from your customer's banking account can cause the results of bouncing off the check payment transaction.

If you've received other specific information like invoice dates and invoicing amounts from the email received, you can track and open the check transaction created in your account to help review which client the checks are for. 

However, if other data aren't stated in email, we recommend contacting your financial institution to help request specific details on which customer is associated with the checks returned from them. This way, it ensures that information is accurately reviewed.

Additionally, to ensure your account balances are correct when handling customer check bounces, you can refer to this guide for more tips and information: How to record customers' bounced checks using Accounts Receivable.

Moreover, I've included this reference to guide you in reviewing your business finances and other payment transactions: Run reports in QuickBooks Online.

We'll keep this forum available, so you can always reply below for any additional questions. We'll ensure to back you up. Keep safe.