Bad Service Billing and Upgrade

On the 1st of Sep 2018 I was incorrectly credited with data on my old plan, after just upgrading my contract and awaiting new device and Sim. I then contacted the call centre and advised the agent that I did not want this data and that I was not prepared to pray for something in which Telkom issued in error. The agent agreed that I was incorrectly allocated data as per my old contract plan and that I should not be billed for this, she then logged the query. On Tues 4th Sep 2018 I then received an Invoice from Telkom indicating that payment is due on 1st Oct 2018 for the old contract plan! I'm being billed for Telkoms error! Furthermore my upgrade came into affect on the 5th of Sep 2018, and I will be prorated for this! Which means I will be paying for 2plans in September! I have not received feedback from the call centre nor have I received any sms to notify me of the case! Terrible service, no communication! Highly disappointed! I refuse to pay a bill for Telkoms error! Awaiting a resolution urgently!