Dulpicate E-mail in Inbox

I have a Blackberry 8830 and am using on a BES Server with Verizon service. We are also using Exchange 2007 in the office. I am receiving each e-mail three time regardless if it is from within the office or outside of the office. I cannot figure out why this is happening. Any ideas?

do you have any forwarding setup to other accounts. also make sure not setup in BES and BIS for same email