able to send email not able to recieve email

Here is the back story, When we signed up for comcast business we set up 2 emails both were xxxxxxx@discfabricsusa.com with one being used for a Amazon store account to keep that separate from our main email accounts for the store/website. The one used for the amazon account recieved emails from amazon as i posted items there then all of a sudden i stopped getting the emails. Didn't think anything of it at the time as i had stopped posting to amazon. Decided to kill the amazon store and recieved no email confirmation of that. 2 days i had to call amazon in regard to the store and the tech wanted me to reply to a email she had sent to that address but nothing came through. I then tried sending an email from our main account but nothing came through. I sent an email from the @discfabricsusa.com account and recieved it and tried to reply but no reply came through. Tried the same thing with the second @discfabricsusa.com email account and same issue. So basically i can send emails from both @discfabricsusa.com account but cannot receive to them. When theses were set up orginally a few monts ago i was on the phone with tech support from comcast as we were having issues getting them set up to begin with. Yesterday i contacted support, they tried trouble shooting the issue, advanced it to tier 2 with a promise that i'd be called later yesterday or early today. No such call came. I called back and was informed it had been closed with no word left for me as to why. I did get a call today from tier 2 support telling me that the whole issue is an ICANN issue because they did not get a verification of the discfabricsusa.com domain. There is no discfabricsusa.com domain....our actual domain is discountfabricsusacorp.com. So either someone from the beginning was wrong in telling us that we could use the discfabricsusa.com as a viable email address or someone today doesn't want to look more into an issue of why we can send emails but can't reveive them. And if it's the first case then someone needs to let me know how i am to go about deleting our 2 comcast business email accounts and setting up new ones that are valid. And someone better learn to contact your customers before closing a ticket so the customer know what is going on.