Translation:The phone is broken
Vunjika is like when an object is physically broken in two and haribika is something that has been corrupted. E.g: kompyuta ime vunjika (means the computer is broken into pieces). Kompyuta ime haribika (means that something inside it like the software is broken)
Phasal verb such as "break down" and compound verbs are very common in English and other indo-european languages, in many cases they may translate word for word between languages in the group because the origin is from an older common root. Eg "overnight-över natten-ubernacht-..." although I don't think this is the case with "broken down"? Swahili is Bantu, phasal verbs are not going to translate word for word unless the phasal verb is loaned from another language.
So according to the notes there is no difference between "the phone is broken" and "the phone has broken down"?
"The phone is broken." can only be formed by the -me- past tense. Therefore literally "The phone has/had been put in the state of breaking.", so "The phone has been broken." A phone that has been broken is broken now. So yes. :)