My ex moving out leaving debt

I was with my partner for nearly 5 years we have 3 children together and 1 from a previous relationship, I have lived with domestic violence for most of the relationships. We live in a family members house for rent free, he has never paid any bills which are now all debts in my name! He got contract phones out in my address but in his name, but owes on those too,he has one phone and I have the other, he wants the phone back... But can he have it back if he owes money at my address?!? He also got a vehicle on finance at my address, the money owed is ridiculas amounts where do I stand with all this and what can I do???