Change of Tariff Plan

Been trying to days to change plan. Been calling their helpdesk with no joy. Dealt with a Sihle who could not assist. Left message for him to call me. To date till waiting for his call. Sent email requesting change of Tariff Plan. No email received on their behalf. Was given a Ticket number and nothing done about it. To date my query has still not been resolved. Tried making contact via Whatsapp and I keep getting same old messages.