Overcharged policy cover

I opened a funeral cover with Momentum FF*** on 31/03/2010 who recently handed over my policy to Metropolitan life, due to said change I reviewed the cover premiums and benefits thereof since there was a notification of the change in the debit order. The child Nkhenso Ellen Mangwane born 09/07/2009 for cover of R 10 000 was charged relatively similar to an adult Senzekile Mangwane born 06/04/1983 for much higher cover R 20 000, those in the same age group as her Erick Maubane 21/03/2009 for relatively the same R 10 000 cover was charged almost half of the premium charged for Nkhenso. Their argument is that her years at inception were less than 1 and hence the high risk, which I quickly interrogated by asking for cover now with the same perimeters with their marketing consultant and by the companies own admission their brackets range from 0 to 9 years in terms pricing and the disparity wouldn't be this severe. To add salt to open wounds Reoratile Maubane born 10/06/2013 was also charged almost half of the premium charged to Nkhenso Ellen Mangwane, to this one feels that they were over charged. Also their closest competitor offers cover for myself and spouse and at least four children at no additional cost. My complaint was met with blatant disregard for Customer Relationship Management (CRM) and customer retention, and Bongiwe Dlamini-Zikode (Operations Manager) who my matter was escalated to, continued with the same rhetoric that since I accepted the offer at inception I must continue paying the premium in spite of this huge disparity.