30-day notice went to Spam!!—what to do??

[Elaine Hester]

Our tenant text my husband today saying that he's vacating in a few days. He said he emailed us his 30-day notice to both of our personal emails two weeks ago, however neither of us received an email from him. My husband then asks him to forward the email, which he did. After seeing the exact date, I started digging through my spam folder and sure enough, there it was. I am assuming it ended up in spam as he used a different email than the one we had on file for him. At this point we are being set back two weeks as I can't get a painter and other needed contractors in there on such short notice. I'd just like to know the specifics on what California law says about this kind of situation, without having to hire an attorney as this is rather minor. Wondering if anyone has had a similar experience and how it played out!🤔