I filed for unemployment in February and immediately registered on CalJobs. I received my first cert form in the mail and completed it, sending it back to the EDD at the beginning of March. I then waited three weeks for a response, and since I didn't get another form I became concerned. I tried going into my local EDD center, but they couldn't do anything other than confirm that nothing had been received on their end. It was suggested I try web certifying, which I attempted but was unable to use because of restrictions on EDD's end. Same thing when I tried Tele-Cert. I tried endlessly dialing the English language line for weeks, and finally had to call the Vietnamese line to set up an appointment for a call. My back pay claim was denied because I didn't cert in a timely fashion.
EDD is not liable or can you show they lost the claim form. There is a risk when you mail something and this is the risk. Also EDD is an arm of the state and thus immune under the 11th amendment for damages in this case.
This is just my opinion and not a comprehensive answer. You assume the risk because this answer may not apply to your situation depending on the facts.