Disappointing Vodacom

On 17/05/2014, we took out a 24 month contract where we received a Nokia Asha 210. In October the phone started to give various errors. Firstly Vodacom said the memory card was too small - hello 4 Gig?? Then it was the one excuse after the other... The phone is currently in for repairs for the 5th time! Every time we get it back, the phone is worse off than before. Vodacom isn't solving the problem and keeps blaming Nokia. We must still pay for a contract which we cannot use fully. Who is now not doing their part of the contract?? The phone belongs to an elderly gentlemen in a wheelchair that is alone during the course of the day. He NEEDS his phone!! How can we help him? Don't know what to do anymore with Vodacom.....