You have a policy for your class, you need to stick with it no matter what.
I feel like class rules are not only to resolve say attention issues but rules instill a sense of awareness that life is about rules and whether they like them or not, it's practice to get used to fact.
I don't think giving into his demands is teaching him anything. A rule broken is like a domino effect, it's messing up more than the purpose of the rule.
If this child has issues then THOSE issues need to be dealt with. This child needs a stronger hand, counselling, and RULES that he's clearly not getting at home which is why he's out of control, running away. etc...
If you can get to him in a relaxed time one on one, explain to him why rules are so important. Let him know that i'm not just enforcing the "No phone rule" i'm also helping you to realize that in the real world we have to answer to others: police officers, your boss, the government (like paying taxes) and you will have your own rules for yourself to feel safe and good about something important to you. I'm enforcing class rules to help you for when you get into the real world. You might not see this now and not be happy with class rules but some rules don't make us happy, they just are a fact!
Being a teacher is the hardest thing, especially these days when children are coming from places where they were never taught respect for themselves or others or basic etiquette, they aren't taught that the mind is a constant child and you need to mature as time goes by.