Confirming emails are not double sending or not sending at all


I am pretty new to and automations in general, i am wondering if anyone has any tips or advice on how to confirm that a email has or hasn’t already been sent to a customer. I will attach a photo of how we currently have it set up, but essentially, we are confirming that the email has been sent by checking out crm status. I can explain what each module is doing and the purpose.

1.) Watch Payments: checking for any new payments, once this is done it is filtered to verify that the status is rather paid or authorized.

2.)Get Contact: Using the contact id given by the watch payments module to find their contact in xero

3.) search items in board by Column values: when a invoice is made, we have in a different automation set it up so it will add their invoice id into the crm. This module (search items in board by column values) will use their invoice id to find their info in (crm)

4.)Create and send email: it first filters to check that the status in the crm is set to invoice set and that 1 bundle was returned. If that is true, it will send them a email where they can book their appointment with us.

5.)Update column values: It will then update the column in our crm to say “invoice paid” instead of “invoice sent”