black child refused dependent membership with with white father

Yesterday I called to find out if my husband can add my son as a dependednt onto his membership. Consultant assured me that it is possible and my should should bring R150 for a tg and his ID. Today they go to Planet Fitness Lynnwood and my son is turned away because he must produce proof that it is his son. They excuse was "they don't have the same surnames". My husband (white male) calls me (black female) to speak to the consultant as we are confused why since we are married. No clear answer is given beside he must get proof of guardianship from Home Affairs to prove this. Many parents have different surnames to their children. Some children are fostered or adopted or become dependednts due to marriage. This is unacceptable. The child was told he is not allowed to use the facilities as it was made clear that he is not my husbands son just because we are married. NICE JOB planet fitness. Disgusting service once again!