Roommate refusing to pay for things brought jointly

Is there a legal way to get my money back from my roommate. The roommate is refusing to pay the money for things that were brought commonly while shifting. I have left the flat now, but it was mutually decided that the remaining party will pay exiting party the set-up cost. I am willing to take less amount owing to the fact that some things are used or damaged in a year, but the roommate is blatantly saying she can pay me only 'x' amount which is barely 30% of the due amount.