can you please enter a option to prove if possible , that some has sent him an email with invoice or quote, now we sent invoices and people pretend they have not received it,
Hi Harry,
You can email yourself a copy of the invoice or quote to ensure you have traceability of what you sent and when you sent it.
You will have access to the invoice and quotes in your email provider's inbox.
Here is a screenshot of how you can do this: