Miway doesn’t pay for OEM parts :(

Claimed for windscreen replacement with Miway as the windscreen had a big crack. Insisted on an OEM and Miway declined the request. Insurance is based on a principle of replacing the loss and Miway insists on generic/shatterprufe windscreen. In my last trade in I was penalised for not having an OEM windscreen. Unfair insurance practice as this Should have been disclosed when I was taking out the policy.