My phone was stolen, how do i stop my emails going on my phone

Assuming you don't have BlackBerry Protect on it.
Call your carrier immediately and tell them to cancel your SIM card.

Did it have a password on it?

Yup i have called and blocked the sim card and changed the password as well....

will the emails be still forwarded ?

Nope i didnt have a password on it

Call you carrier - they have the IMEI for your phone and tell them it was stolen. They will bar it from their network.