Telkom Overcharging & going against contract

Mid November 2015 I app**** for Do Basic @ R399 including line rental and installlation cost.<br> After numerous calls it was finally installed on 04.01.2016 - 6 weeks compared to 2 weeks promised.<br> 10.01.2016 I receive my first bill, I am shocked from expecting bill of maximum R798 (JAN/FEB @ R399X2 Months) I end up with a balance of R1,111.45.<br> 13.01.2016 Go in store to correct just to be told I must contact the call centre.<br> 14.01.2016 I contactedthe call centre to be told the bill is correct as installation was R573.68. I informed them this cost was included which resulted in them informing me this is incorrect even though it was confirmed in store when I signed the contract. I then said either the cost must be removed or my contract must be cancelled and I would find a telecommunications company who adhere's to their advertising. At this stage I was told if I cancel the contract I will be charged the full 24 months.<br> The customer service is completely unacceptable and the fact I am just expected to accept the extra costs is ridiculous.<br> I will not be held liable for the contract when Telkom did not adhere to the agreement.