selling misrepresented goods knowingly

I bought the VERSSED Motion E1.1 tablet with keyboard from Jet Barberton 02/11/2015 - first you are informed that you must charge the device for 16 hrs before using it...on the packaging you are informed that you get 8gb internal memory ...after charging it and installing the apps etc that I need...I discover that I got 4gb internal memory instead of 8gb!!! I took it back to jet 04/11/2015 and spoke to the sales person (mentioned) above and was informed that he knew about the problem! I also pointed out to him that the tablet has only 3hr battery life! And that it came with pre-installed apps that DO NOT work!!! He was also aware of the fact that the Telkom 8ta sim-card was useless and could not be activated!!! Apparently The misrepresentation and lies of the salesperson and the manifacture of the tablet is now nobody' problem but mine! I desperately need a proper functioning tablet - have been sold a pack of lies - can you help me please?!?!?!