the "Debugging eCart transaction failed issues" tutorial on the eCart support page walks through getting the error response bindings for the payment gateway:
you can add the short error message binding to the page to show the user a message about why the transaction failed.
There should not be a limit to the notes form field. The styling of the email message may be causing the notes to appear to be truncated.
try moving the notes to it's own line instead of being on the same line as other bindings.