flawed IT system

On 30th of June I transferred R3000 to my card from my cheque account - internal transfer. Technical error occurred and the money disappeared. Two phone calls later I was assured the money is back in my account but it disappears again. I phoned for a third time this morning and the money shows as an overdraft which will undoubtedly disappear again. I realise it is not the poor friendly consultants that help me and escalate to IT that is at fault there is something wrong with the system and Mercantile's IT department is unable to correct it