Network Lock Phone issue

I have taken out a Vodacom cortact @ Game recently. the phone that I got was a Aspire 5 Smartphone. I gave the phone to my wife but she is using a Telkom simcard. when I insert this sim card, there is a network lock error which requires a pin code to unlock the network on the phone. I went to vodacom in kolonadde, they said they dont have a technician and referred me to Vodacom Menlyn. I was at Vodacom Menlyn on Sunday, Simon book in my phone and called me yesterday to inform me that the "Network lock" cannot be removed. My concern is this: The phone enable you to insert a code to unlock the network, yet nobody knows what the code is.... now the easiest way out is to inform me that the phone only uses Vodacom sim cards... this is really unfair and I feel that the information wasnt given to me... no transparency at all. I am a loyal vodacom client for many years...