He's trying to force you into communicating with him. Trying to convince you that he will always find you and you might as well give in, as he can't be stopped.
Once upon a time, one of my exes did similar - I didn't respond and changed my number fairly quickly. In that intervening period, he messaged a number of times saying things that made it sound as though he knew exactly where I was and what I was doing. However, even things such as 'Nice top', 'Your hair looks good like that' or 'I can see you right now. You've just turned your bedroom light off' are fishing for a response and to make you feel as though him controlling you and owning you are inevitable. Even responding 'Don't think so' to 'I've found your car/house' is suggesting to him that he needs to cross that particular area off and look at the other likely places. There will be messages 'saying goodbye, I can't live without you', claiming to have taken overdoses, be sitting at the top of a cliff about to go over, comments about 'your new man', threats to him, messages that something terrible has happened that you need to know about, serious illness, fire, theft and plague of locusts. None of it will be true - it'll be to drag you back in to communicating and hopefully letting slip something that'll make it possible for him to find you.
You need to completely refresh all your personal security - not just block him, but changing your privacy settings so that if you get tagged on something, he can't see it - Friends only, not Friends of Friends, you're not searchable by name, email or phone number, new number for WhatsApp, no 'find friends through your address book'. No posting on public pages.
The council won't mind if you get a camera doorbell fitted. The cost of continually recording/saving the footage will be invaluable in terms of peace of mind and, in the worst case, providing evidence. Get a camera for your car, as that will show if he's actually been near it.
When it comes to missing physical contact, yes, that can be difficult at first. But you have your DC. The feeling tends to go after a while - and you will most likely feel your flesh crawl at the thought of him touching you once you look at how scary stalker he is being even when you've left him. He used that touching to get away with abusing you.
You can do this. You will do this. You are doing this. For a shell of a woman, you've obviously got a thin steel core running straight through your middle. Which is pretty good going in my mind.