Stating that AXA covers all pre existing illness is kind of misleading bro.
The insurance contract is an offer and acceptance process and if you have receive a letter confirming that the insurer has accepted your diabetic condition without prejudice, then you can safely say they will cover it. Otherwise, it is not properly declared.
More importantly, you had not made any claim in respect to diabetic, for example organ failure, amputation of limbs or blindness which relates to being diabetic.
Should a claim were to arise, and the amount is huge, it may trigger the non declaration of material fact which may void the policy.
AXA or any other insurance company is not doing it for charity. I had also gone thru AXA brochure. The first thing on the Exclusion is pre existing illness.
Dont get me wrong bro, the reason why i say we cannot offer you life insurance is because i dont want you to end up paying for something useless and later you cannot claim.

Since your company did not providing the service, do not assume that you know everything about insurance from top to toe. There are insurance that do cover pre-existing illness. It's ok if you don't know about it. We are all learners and we are in process of getting to know things gradually not up straight. I have attached the part where AXA includes the plan for your knowledge.