When is Comcast going to have better e-mail? One can't tell if an e-mail has been sent out or not. There is no 'sent' folder.
There IS a 'Sent' folder. The access method/settings to your email isn't showing it to you. How are you accessing your email, e.g. what device, app, browser, etc?
Just the Comcast website. In the mail folder. One has to be a programmer these days to figure out anything online.
What device are you using to access the website and what browser? Maybe someone can duplicate your issue. Seems like the Sent folder is just 'hidden'.