BlackBerry Curve 8330

I'm confused, i've called Sprint and BB directly and no one has an answer. I recently set up my corporate e-mail on my Curve. It worked fine for a couple of hours, but now I don't recieve corporate e-mails. I still get calender updates and can compose using my corporate e-mail, i just don't recieve them. The IT people began talking about BES and BIS and what I had. They just confused me even more. If it had anything to do with the account I have, why would it have worked in the beginning? And why can i send e-mails and recieve calender updates? Anyone out there having similar problems?