How to interpret an insurance policy's verbiage?

I am in the process of getting on disability insurance through work. The disability insurance has the usual 2 page brochure and then if you want you can access the 50 page details document. In the middle of the document it says no coverage for any disability which is present prior to the date of coverage starting. However a condition which is present that is not disabling prior to the date of coverage staring will be covered. This seems like it is very vague.

Say a person has had a cancer before they got on this insurance. The cancer was stage 3 and the person was disabled for a duration but has been cured of the cancer for many years. Under this policy would that mean a cancer diagnosis is not coverable because it was disabling prior to the policy starting?

Or does the policy mean the very day of the policy starting any/all disabilities present (or conditions that are disabling) are not covered? I have neurological things that are controlled through medication that are not disabling at the moment. However they could become disabling. I'd call the customer service number but all I get is a voicemail and no returned calls. How should I interpret this new insurance verbiage? The policy is a disability and life insurance policy in one.

Location: Wisconsin