Hi i'm completely new to blackberry and i have a curve 8520.. i just updated my phone and now have the bbm 5.0 and hate it :( i'm trying to restore it to the old one but have no idea how to do it on desktop manager on my MAC. could you please help?? :(
You have to revert to an older OS, probably the one one that was originally on your PC.
The best way to update the OS is to use a Windows PC. Set up a Windows instance on your Mac using BootCamp, Parallels or VMFusionWare, or find a friend with Windows XP or later.