e-Mail Issues on SAAB

[osirion]

Ok I never use the forums for support really but this is urgent.
I tried live chat and they cant figure out whats wrong. I tried e-Mailing support@hostgator.com but theres where the issues lie (email) so that cant help me much as I cant even read my ticket auto-response with the ticket #

Heres my e-Mail again (slightly modified):
Good Day,
I and my clients are having issues with e-Mail recently (last few days).
Apparently both receiving and sending. I have hardly gotten any mail (though some is coming through and some going on some of my accounts) - though I know that people have been sending me mail and I have not received it (multiple people on different domains/networks).
I have also sent out mail and have noticed that people are not receiving it.

On the client side the little e-Mail that does come through receives fine (no errors - etc). With sending, I also don't get any errors - etc.

Server: SAAB
Server IP: 67.19.186.2

If you could please check this with utmost urgency. It is the 1st and I need to send out invoices today!

Once again this is not a client side problem as the mail that is on the server gets received fine and the mail I send; sends fine (to the mail server).
The issue seems to be once it gets to the server that it doesnt go (or come) any further.

I have spoken to lots of people that have apparently sent me mail and I have not yet received it (going on to) 2 days later. I have also tried sending myself e-Mail to a free webmail account I have and not received mail on that account from myself (only other people).
Usually delivery receipts (this email im testing with; ***@webmail.co.za; the mail server does send out delivery receipts) and they usually come within 5 minutes or so.
It is now a couple of hours later and no delivery receipts nor is there any e-Mail on that account I sent the mail to (from my HG hosted e-Mail).

This seems to be affecting not only me (osirion.co.za) but other domains (my clients) on the SAAB server as well.
PLEASE HELP!

ITS THE 1ST AND I NEED TO SEND OUT INVOICES; I ALSO HAVE OTHER TIME CRITICAL EMAILS THAT I REQUIRE TO RECEIVE.

[osirion]

Thanks to Steve from support@hostgator.com for sorting out the problem.
Just for everyone's information; it was actually a file on my site which submitted an e-Mail to us for newsletter signups.
Insufficient checking on the scripts side made it exploitable to send out spam.

I am going to review the file and make the necessary changes to it.

Thanks once again HG!