Life Event Enrollment requires proof of loss of insurance?

Hi all. I recent quit my job. My family’s insurance was gone with that job. My family now is trying to jump on my spouse’s company insurance because loss of job is a life event for enrollment. I feel that my wife’s company HR is being unreasonable by requesting for overly specific evidences. Her company HR demands a letter of termination of benefits specifically with Names of every family member, type of insurance we were on(visions, dental, supplemental life, every type of insurance we want to be enrolled my be specially mentioned in the letter), and end dates. I finally got one letter that from my ex-company that just states that I as an employee lost all benefits but that apparently wasn’t specific enough for this HR to start the enrollment process. After hours on the phone, I finally got my ex-company to send out a letter that has our entire family names, medical insurance type, and end dates. But, We still couldn’t sign up for vision and dental or life insurance because that letter only mentioned medical insurance. My 30 day enrollment deadline is coming up in a week. Isn’t the loss of my job enough to trigger conditions for life event enrollment? For arguments sake even if I didn’t have insurance, I should be able to sign up for insurance at my spouse’s company correct? Or is lifeevent a special thing? Please help and advise. I am in Utah. And wife’s company is a multistate corporation.