Terrible Customer Service from Lebo at MTN Greenstone

I would like to lodge a complaint against Lebo, who claims to be the manager of the MTN Store at Greenstone Mall. I have an MTN 4G ****le that stopped working. I took it in to greenstone stores for it to be checked. Lebo said checked it and said she needs to book it in. She also said it will take 3-4 weeks to get it back. I told her that I could not wait 3-4 weeks for it as I use it for work and needed either a replacement, or a temporary unit until they resolved the issue with mine. She referred me to the signed CPD saying it should read the Terms and conditions. I reminded her that the T&Cs of the CPD does not stipulate that repairs with MTN will take 3-4 weeks, leaving us out of service for so long. To which she rep**** we are done at the counter and she does not want to help me anymore When I asked to speak to the manager, she said she was the manager, yet I know fully well she is not the manager of the store. She could have offered to sell me a new device as a replacement, at a discounted price in exchange for the old broken one and I would have gladly considered that option. Please get your team properly trained as this is unacceptable. Now I bought a new device, so I want the old device to be taken back by MTN and I want my money for the remained of my contract term to be removed from the bill.