NO AIRTIME TRANSFER

I COULD ALWAYS TRANSFER AIRTIME FROM MY CONTRACT NUMBER TO MY WIFE'S NUMBER NOW ALL OF A SUDDEN I HAVE INSUFFICIENT FUNDS BUT THERE IS R 900 AIRTIME IN MY ACCOUNT ACCORDING TO VODACOM MY TRANSFER BALANCE IS DEPLETED I CAN ONLY TRANSFER R 2 AT A TIME 80% OF MY BALANCE THAT IS MADNESS I MUST TRANSFER R 100 R 2 AT A TIME