Roommate to Roommate Security Deposit

My question involves roommate to roommate in california: In a nutshell...I'm a single mom and had a couple, (boyfriend and girlfriend) moved in about 6 months ago. Paid $400 cash security deposit. They turned out to be quite the party animals. Boyfriend would get drunk and urinate in his sleep in closets, livingroom, etc. When they moved out, hole in wall had been patched (wire mesh sticking out of it) - had to be redone and painted, did not clean..just moved their stuff and left the key on the table with no final walk-through. I itemized a cleaning bill for them ($200 from the $400 minus the $135 they owed from last month) and offered them $65 back. The girlfriend thinks she should get $200 and shouldn't have to pay the last months part of the utilities. Father of male roommate is threatening small claims court in an effort to strong arm me into just giving in.

Any suggestions or insight into where I stand legally?

Did you follow California's security deposit law to the letter?

no letter regarding walk through...they were suppose to come back that night and then flaked and called it off. Other than that yes. Itemized what expenses there were and deducted for utilities still outstanding and offered the remainder balance to them. They didn't like it and got their dad involved who threatened small claims court to get me to give in and give up more money to them. I don't think the dad got the full story from them.