Check your other thread in this particular forum. We are going to need to know which version of Partner PHONE SYSTEM (not telephone set on your desk), and which Voicemail system you are using with it, along with what other modules are in the cabinet (maybe post a cell phone picture). Then directions can be given on restoring the previous settings, or at least getting the system back to being functional.
What is happening is by default, every call rings to every extension. The voicemail system is 2 or more extensions, and all voicemail ports are trying to answer the incoming simultaneously. When one of them grabs the call, normally the phone system sends some signals to indicate what to do with the call, such as answer with the auto attendant, answer with someone's mailbox, answer with the login prompt. When it doesn't get that, it just transfers to Ext. 10