Poor and totally bad service

My horrific experience with Telkom started with the Black Friday Special(24 Nov-17). I have app**** on-line for Huawei P10 lite (R199 x 24 months). All my details where taken by a sales consulted the next date. My contract was approved and within the week (01 Dec-17)my first debit of R199 was deducted from my account. Expecting my cell phone to be courier to me by 3 working days. 1 week goes by no phone, 2nd week no phone. Call the call centre number after 30minutes waiting on line, only to be told that Telkom has no stock. Then managed to speak to Manger(Nathi) who assured me that he with sort out my issue ASAP. 18 Dec-17 received a SMS that my order can be tracked via Telkom approved courier company. Received the consignment on the 19 Dec-17, only to find that they have sent a router instead of a cell phone. Call the call centre , waiting over 20 minutes to get someone to talk to and inform them of their error. 2 days later, courier pick up the incorrect device to take pack to Telkom. 15 Jan-18 call again, to the call centre about my cell, only to be told the correction will be done now, and the correct device will be sent ASAP. on the 19 Jan-18 received my correct device. I thanked God that my issues with Telkom was now over, only to get the next shock where I received my billing from Telkom. I was now bill for the incorrect(router) and the correct contract. 08 Feb-2018 call the centre again to rectify the billing issue, only to be told to email my invoice to them, which I did. Received an email confirming this as well as a reference number ********** 25, forwarding the email to Manager(Nathi). No response after 5 working days. Sent another email on the 6 working day. What must I do, to get Telkom to sort out their mess they have created. This is contrary to "GOOD BUSINESS PRACTISE". This is the main reason that our state companies are in a mess, and we the taxpayers need to bail them our. They cannot get simple things correct first time. It seem that top management sitting in their ivory towers, and don't care of the inefficacy, blunders, and total poor service dish out to their valued customers.