Raw deal from third party cellular phone service providers

I recently entered into cellular phone contract with a company called Intellicell based. This was done telephonically and sell their phones on behalf of the major cell phone companies e.g Vodacom. To cut a long story short,I used the Nokia 3 for about six weeks and the device froze and can't switch it on. I contacted intellicell and was told to go to Vodacom to book the device for repair . I did so and was told Vodacom technical that I must produce proof of purchase,which I don't have. I called intellicell again so that they can send me proof of purchase,only to be told that they don't give proof purchase to clients. As result of this I am stuck don't know what to do with a none functional device yet I am paying too much for something that is not working and still under warranty. The other thing that worries me is that the company does not have a physical address and landline phone number.they only use this no. ********** 246 which is expensive to call. Please help me to resolve this matter between myself,intellicell and Vodacom. I actually want to get out of this contract since I am not getting the services I agreed.