Postal Locations

I own a business in Anaheim, over 40 years. Some days I don't get mail, the usual time the mail man delivers is around 5:00-5:15 pm. We close at 5:30 pm. Now my customers are hand delivering their payments in an envelope with my correct address on it and a big yellow sticker on the front that says "return to sender not deliverable as addressed unable to forward. Does anyone at the post office know how to read? This is getting out of hand, the post office has horrible delivery service and down right lazy people sorting your mail. Who can I talk to since no one answers the phone. THIS IS A BUSINESS FOR GODS SAKE.

I didn't receive any mail for three weeks. The last mail delivery I got was July 6th, 2020. I went to the post office on Loara st. In Anaheim, Ca. The supervisor there told me that she would call me and nobody helped me. Where can I call to make a formal complaint? I need my mail.