What could happen is you call an automated database that is part of your phone provider's system link to all cell phones, this database then asks you why you are unreachable, you record an answer, next it asks you between which dates you will begone, you record an answer. Also, since you called the database from your cellphone that will be out of service it automatically recognizes which phone to apply these settings to. Now, when you friend tries to reach you and fails, the phone company and reply with a complete automated/recorded reply.
Next, for you "ignore list" there could be a program that sends a list of ignore numbers to the same database that is part of your phone provider's system link to all cell phones where the system "picks up" the phone and then immediately hangs up, so that they can't leave nasty messages.
A simpler way to solve "Step 1" is to go into your phone's "settings" and change your voicemail recording to say: why, where, and for how long your phone will be unavailable.