I refunded too much of tenant's security deposit! Help!

[Ed B.]

I made a math error and refunded too much money to my ex tenant after she moved out. I alerted her to the error and asked for the overpayment back, but she refused. My only option is sue her in small claims court. Has anyone else made a similar dumb mistake, and if so, what did  you do about it?  Did you have any luck suing in small claims court?  Is anyone aware of any law that says such errors are not correctable if the overpayment is in the tenant's favor? This happened in California.  Thanks