Frustrating as always

I upgraded less than 7 days ago, but to my surprise the new phone has issues from the start. From the first day the battery does not last even 6 hours, while it is advertised to last 2 days, it is extremely slow, it overheats, the screen is not responsive (does not react to touch as it should), poor screen resolution/ quality etc! Needless to say I feel cheated! I receive a call from a nice guy from Vodacom and I explain how frustrated I am, he informs me that I can take the device back within 14 days and they have to replace it. Get to Vodacom Shop Festival Mall and the agent can't help me so she calls Fikile Khosa the sales manager who blatantly refuses to help me. After showing her physically how frustrating this useless phone is, she phones the store manager, David de Beer (who was absent) and then confirms that they will not replace the device, but wants to book it in and send it to the repair centre. Then Fikile refuses to book it in because I did not have the two-prong USB plug in the box (I had the charging cable, headphones, user manual etc. everything I got in there). Now they expect me to take back the phone tomorrow, only to book it in and I have to be without the phone for weeks, with no intention of replacing the phone or any prospect of improving the situation. Blatant disregard for the fact that the sales consultant did not explain that the XA is the worst phone Sony has ever made or any regard for the fact that I am extremely unhappy and that I have been cheated into a very ****py phone for two years! This has to be covered by the CPA? Do I now have to take legal action or lay formal complaints just to get this sorted out?