Ex Gf's Bf Threatening To Hurt/kill Me

To summarize things shortly my ex girlfriend's boyfriend and his friends are constantly harassing me, and sending me death threats. For example they keep spamming me and texting me on multiple burner phones,(probably using the burner app or something like it). I tried asking them what their problem was with me multiple times, and constantly I get denied, or just ignored. They then proceed to ask for my location and address multiple times because they don't know my exact number of my house but they know the street name. I can only assume my ex ended up giving out the info to him. I have contacted the police multiple times and they said they simply cannot do shit unless he's ACTIVELY BREAKING IN. For context this is a girl I dated 3-4 years ago and have done NOTHING wrong with. They have somehow found out the current girl that I've been with for almost 2 years Identity. Need help asap.