Can anyone recommend a collections agency in Southern California?

[Roshni Patel]

This is the first time I've had an outstanding balance from a tenant that I need to collect on.  They came into a large sum of money and ended up purchasing a house, and still left a ~7k balance between past due rent and damages to my property.  Looking for recommendations for a Collections Agency and any advise on how to collect.  I've already emailed and sent them a certified letter of the list of damages (and photos) and detailed invoice of the amount owed.

[Alex Talcott]

I'm a lawyer and partial to local landlord-tenant lawyers.