Not happy with the service from Telkom

I bought a cellphone online with Telkom and they delivered the phone on the 6 August and immediately I noticed it actually not the device I requested and I called the sales team on the very same day. I have been calling them everyday because already they have debited the money from my account and since from Monday I was told that they are allocating the sales consultant who made the sales. I called again today after I kept on calling since Monday and even today am still waiting for them to get back and my 7 days period is ending tomorrow even the people who I was talking to are telling me different stories, others are telling me I can change it in the store and others are saying no whoever made the sales needs to arrange to get back. With the bad service am receiving its clear that I need to use a device I don't even like and I wont do that. I will block them from debiting for the phone and I wont use it until they come get it because I don't understand why I must get hold of the sales person when they work for the same company and if its commission based the person should only receive commission after 7.