My question involves employment and labor law for the state of: California

My employer has issued me 9 payroll checks that have been returned. The earliest in July 2011, the latest 2 weeks ago. I have asked several times for reimbursement, and have written a "polite" demand letter with copies of all the checks. I am afraid of losing my job by getting too aggressive, but I need to be paid. I have done a little research online, and think I understand waiting time penalties for returned checks, a days pay for every "waiting" day up to 30 days. My question is, am I entitled to 30 days pay for each check? This would be 9 months pay in waiting time penalties.