Extremely disappointed member

I requested to remove my son adult dependent son from my plan, on 28 November 23 wef 1 Jan 24, giving 30 days notice, since he has gotten married. Bankmed removed him wef 1 Dec 23. He has already joined and been accepted as a member on another scheme from 1 Jan. He will now not have medical aid for a full month, and waiting periods will apply on the new scheme since there is broken membership. They refuse to add him back as a member as he is no longer eligible to be a member because he is married. It is not acceptable that they removed him without informing us and that they don't want to correct their mistake. They promised the manager would call me back in 10 minutes, but she never did.