HELP! Issues receiving emails

I am not sure if this is the proper place to post this, but I can't seem to find help any where else. I am having issues receiving emails from tykamerica.com. I contacted our IT department and they said that they can see that the emails are being refused on the network level. It is only emails coming from tykamerica.com, we are receiving emails from other addresses and comcast.net emails are the only ones that they can't send. Where do I report this issue to get help?!?