You may have thought you saved yourself a lot of money by buying off ebay but I think you are going to find that isn't the case. These systems are not plug and play or meant for the end user to install and program. Your system may have serious problems or it may have programming issues. At any rate you are going to have to have the admin password reset for you to create your own menus. See the
Avaya-Lucent Posting Information , the very first topic at the top of this forum for information as to how to get your admin password reset.
Since this is a used system both the processor and the messaging system should be defaulted and programmed anew from scratch to your requirements. This is the only way to eliminate any "bombs" that may lurking in the last users programming. Possible that a programming error is causing your phantom ringing, maybe not.
I would suggest that you contact a local Avaya dealer who, for an hour of time will take care of this for you.
-Hal