False advertising Vodacom 3G Tablet

On the 27.11.2014 Vodacom offered me a Vodacom smart 3G tablet at R50p/m delivered free of charge to my place of work. We entered a verbal agreement which was confirmed on my Dec statement (even specified black as the colour). Delivery was supposed to be at most 10days. In January 2015 after extensive inquiries, I was told they were out of stock but would receive my tablet as soon as possible. Today (13.03.2015) I am told they are out of stock yet they have launched a promotion for the exact same product at R89p/m without honouring their obligation to me.