Dispute for newborn waiting period

Bonitas is refusing to cover my newborn child, even though I had sent them all proof that I had send the application within the month period after birth, they had confirmed on a previous mails that they were in a process of registering him from birth , and they kept quiet when I continuously inquired after two months of them not attending to the query, they blantly placing my child on a 3 months waiting period, leaving me in financial stress