MTN refuses to honour warranty

I wish to make a complaint against MTN. My previous complaint mentioned how MTN had not responded to my requests of what happened to my son's Blackberry 9320. I asked a friend of mine to call their high volume repair centre to ascertain as to what is happening with his phone. One of the call centre agents told my friend that the phones LCD had been allegedly cracked thus the warranty was voided. They did however acknowledge that the trackpad was faulty but said that as the LCD was cracked thus the warranty no longer app****. My friend asked for photos as proof that the LCD had indeed been cracked. The agent promised within 24 hours it would be sent however it was not and again MTN was phoned and he was told that the request was logged on the system and that they were waiting on the technicians to supply the photos and that it would be done Friday or Monday latest. It is now Tuesday and the photos still have not been sent. My friend found out the cost from a certified level 4 repair centre. The cost for the LCD is R399. MTN wants over R1000 just for the LCD. I cannot afford this as my son is unemployed. MTN refuses to give the phone back, they want R300 just for looking at it.