Why are drunken yobs so pathetic?

So much so that they choose to victimise, torment and terrorise a young single woman living alone instead of picking on someone who can defend themselves? Every weekend I have people vandalising my house and peeing on my terrace and if I come out of the house or come home late alone they threaten and verbally abuse me. I have a big dog but she's not much of a guard dog - too soft- and I can't afford to go and live in a better area. The police refuse to help as it happens late atnight and "they're not around" wtf?!? PS I live in Italy,starting to regret it.