false Sales,billing

As one of many customers I was told that I would pay R150 but I ended up paying R1700 when I ask they told me they will invistigate I will have to wait 7 working days I'm inconviniaced what about my other debit orderes 2 they said they I will have an access of wi-fi when I'm in the mall when I asked for pin to use that service I was told they didn't complete my application and I'm still waiting for them to complete it.On top of that yesterday I received an sms saying that their records shows that I have not paid so I must do so immidiatly