Thanks Sharla, I now have the right chart.
I make a distinction between the call and the caller (the message and the messenger). The call is third house and is the Moon. That the call is malicious is shown by the conjunction with Saturn, as the Moon is seriously afflicted.
The caller is either an open enemy (being in the seventh) or a secret enemy, but the only planet in the twelfth is Mars, and that doesn't make an aspect to the call. Jupiter, ruler of the seventh does make an aspect. there's a sextile between Jupiter and Moon/Saturn (though a wide one). But Jupiter and Saturn have a mutual reception by Ruler (Saturn rules Jupiter) and Exaltation (Jupiter is in Saturn's exaltation. Moreover, Saturn is the Air Triplicity ruler so the link is strengthened. Jupiter is also Retrograde and so not as benevolent as you might expect.
On this reading, it would be Jupiter that made the call. Someone who is openly working against you and clearly doesn't like you. Jupiter is in the fifth house, so the link could be something to do with Children or something to do with your leisure activities. Someone you meet in the course of enjoying yourself.
Jupiter also rules the eleventh house of friends. interestingly, that is where your significator Mercury, lies and nearby is Venus ruler of your twelfth house of secret enemies. Venus is also Retrograde, and has a mutual reception with Mars (Ruler/Ruler), as the eleventh stretches from Pisces into Aries. That might suggest a second person is involved here. someone who you see/saw as a friend but has distanced themselves from you (not necessarily physically)
Venus also rules the fifth house of Libra, wherein lies Jupiter. so this looks like' friends' rather than neighbours.