Mtn
Awaiting for Samsung SII phone for 9 months

I took a Samsung SII cellphone with MTN in Novemeber 2012.
The phone went faulty after two weeks which MTN told me that they replace it since it was under warranty.
I was given ref no COL0030149048 to collect a new phone. I have been to South Gate Mall 14 times to collect phone and I was told it's out of stock.
I have been to THE GLEN Mall and Benmore Garden Mall to collect a phone but I was told they are out of stock.
I have travelled 240 KM back and forth to the store (to collect a phone that MTN does not have. They don't even care that I used my petrol and time to check if the phone is available.
They blocked the sim Card in March 2013 and I am still being charged for the phone and airtime I do not use. Now they want to list me my name to damage my credit record.
It's been 8 months now and I still do not have a new phone but they are still billing me. I want to cancel my contract based on non-delivery on MTN side and they are threatening with legal action.
I have the following ref numbers to proof that I have done everything to get MTN to resolve my problem:
9602758, 6107441, 6170406, 1828778, 6172178, 6402243, 6402691, 6572926, 6755143 and 6758924.