ALL TABLETS FAULTY!!!

I bought a Vodacom Smart Tab 3G from Pick 'n Pay, Mokopane. The tablet could not keep power even when it was not in use. The battery lasts a little over an hour and constantly needs to be charged. I returned the tablet to the store and they gave me another tablet with the same problem. I kept returning the new tablets and now I'm on the fourth tablet with the same problem. I think this batch of tablets has the same problem. I also didn't receive the 1GB Vodacom data which was part of the promotion. I would like Pick 'n Pay to give me a tested and functioning tablet or give me a full refund.