Unpaid Work Hours For The Last 7 Years California

Trying to make this short and make sense,

Our work offers an afterhours program (which is voluntary now) where you get paid a certain amount for every phone call you take. Apparently I was supposed to log every phone call start to finish (searching for customer needs) and clock in and out when arriving at work to hand goods to customer. I was never told I was supposed to log every minute and clock in and out when arriving at work. What brought this up was a new policy form they want us to sign stating this information I just provided. However they did pay the fee I was promised for every call, but I wasn’t aware of the time I put in that was also supposed to be paid. Apparently every other location paid their coworkers except mine because my manager was unaware of this. I did probably 20-50+/- calls a year. How do I get compensation for all the missed hours I put in for all the last 7 years? I emailed HR but it’s been 2 days and no answer “they notified HR manager” but haven’t heard anything. Let me know your thoughts? Thanks