Making joining very difficult...incorrect billing

I am writing on my own behalf and for my son Michael Adriaan Potgieter who is having a very bad experience trying to join Discovery Health.I am a long time member of Discovery Health with my son being on of my dependants.He was in a position to join Discovery in his own name from 1 April and as his salary gets paid in after the 1st he asked for the option of the debit order to go through on the 10th of the month.The first deduction went off incorrectly on 10th of March placing his bank account into the negative.He called them and was told it was a mistake and the amount will be refunded which it was.However he then got an sms that his medical aid has been suspended because of no payment.After another call they said this will be corrected and the first payment will go off on the 10th April.However on the 10th of April two months payment was deducted putting his bank account again in the negative.At the same time I was also still debited for both of us on the 1 April.Can somebody just please sort out this mess and refund what needs to be refunded and confirm that his medical aid is now active.Regards DJ Potgieter