If both you and your roommate is on the lease, the rental office should split the deposit and mail to each of you. The manager obviously is biased. If you don't receive your half from your roommate, you should complain to this manager's superior of never receiving your deposit and she should never sent your potion of the deposit to your roommate in the first place knowing you two had conflicts in the past. You sounds like a nice person. My other suggestion would be for $150 maybe just let it go. For the kind of low life like your roommate, your effort can be better spent elsewhere than dealing with her that may cause more agony.