Vodacom Park Station Shop are ******

I bought a R3000 phone from a shop branded with Vodacom all around, inside Johannesburg Park Station because I urgently needed a phone before boarding a bus. They told me, it has a 1 year warranty, and gave me a slip as proof of my purchase. The following morning, the screen was not working at all. And there are no signs of phone falling or sitting on it. I took it back to them, and they said the warranty does not cover the screen. But the terms and conditions of the warranty in the slip does not include screen breakage. I fetched police, "Vodacom" took my phone and said they'll get back to me in 3 weeks. Three weeks went, and I called them today and they say I must pay an extra R1600 to fix the phone or just fetch it as it is. I have the slip with me, I can post photos of it here. I'm really lost on what to do, because I did not break the phone, and I'm beginning to suspect that, it's not even a Vodacom shop, even though the branding says so. But why is it inside Park Station? Why does it says Voda Shop outside? Even the slip says Vodacom. Somebody please help. Can I open a case?