Bad service after wrong upgrade

I upgraded through Mobiles Plus (MTN) requesting a Gold phone to the agent on my upgrade– and after being promised a Gold phone I received a Black device which I have sent back immediately after delivery. It has now been weeks since I have sent it back and every time I speak to an agent they either tell me this matter has not been reported yet or that they are working on it.

They have told me to go in store to MTN and in store they tell me that there is nothing they can do from their side since this is a Mobiles Plus upgrade (which is a different division). I find the service of Mobiles Plus appalling because no one takes responsibility for this situation and the agents are very eager to sell a deal to a client but when something like this happens they don’t take any responsibility.

I am already on my new contract but still have no phone for more than 4 weeks.

They will not replace the original black phone they have sent me with a gold one (as requested) - they told me that this contract first has to be cancelled and then i can go and re- apply for another contract to get the colour i originally asked for.

I cannot upgrade in store before this contract has been cancelled by them and till this date they have not cancelled the contract. I have asked them many times when this will be cancelled and failed to receive and answer. I currently now pay for a contract and phone i don't have - i will never use them again.