ABSA Insurance does not cover motorcycle when 16 year old child with valid learner's license ride it

We registered a 125cc motorcycle with ABSA insurance 2 years ago (2015) with my oldest (then 16 years of age) as dedicated driver. As, by law, he had a valid learner's licence. (You can only qualify for a 125cc motorcycle licence when turning 17.) We bought a second 125cc motorcycle in 2017 for my youngest, now 16 years old, also having a valid learner's licence. ABSA now refuses to insure my youngest as he does not have a licence. I was even told that, had my oldest had an accident having only a learner's license, they would not have even paid out, as he then did not have a licence. ABSA insurance willingly took our insurance premium for a year. Iwyze also refuses to cover the motorcycle. Why do insurance companies not cover 16 year olds with valid documents? That means there are probably many children in South Africa riding motorcycles that are "supposedly" covered, until it comes to payout time?