Unrealistic Waiting Periods

My husband and two kids have been on my husbands medical aid plan, membership number ********** , we decided to move them to my plan as my husband started a new job and was paying for the medical aid on his own. Whilst my husband was with his previous company he was charged in arrears however when he moved companies he was under the impression he was paying in advance and therefore thought he had cover in the month of September. He also received communication from Discovery advising him his policy was reinstated in September. I requested the kids and my husband be moved to my policy in January 2019 and was then advised we had exceeded the 90 day no break in cover and therefore my husband who is Diabetic will have a waiting period of 12 months and my daughter who has a heart murmur will also have a 12 month waiting period. I have asked the new business consultants to relook at this as this waiting period will be detrimental to their health. I have offered to pay for and start their cover effective 1 December 2018 alternatively my husband can pay for September which will not exceed the 90 day limit. The mitigating circumstances are that both my kids have been covered by Discovery from pregnancy, and my husband has been with Discovery for over 15 years. Kindly relook at this and advise.