The security on medical aid is bad anyone can buy with your medical aid

I love Heidmed's service, but they need more security measures when it comes to medical aid, because my stepmother has my medical aid number because she looks after my daughter while I'm at work and she will go buy on my name, my husband name or my daughters name. (my daughter is 7 years old) but she will buy stuff like ,MYBULEN and adco-dol and say its for my daughter. I'm really getting fed up with this because a pharmacist must know that a 7 year old cant drink that meds. I think they should ask for a id when someone buys on medical aid. If I see one more mistake like this I will go to the medical aid and complain about *****.