Breach of Contract

I sign a contract over the phone for a 24 month contract at R649/m for 24 months #INC-***. They phone me 2 months later today and said they cancel the contract due to no stock and I am thinking now that this is actually very unfair because it was not my fault and that it was DSTV that could't delivered the HD Ultra Decoder. We actually signed an agreement over the phone and I want you to stick to the agreement of R649 for 24 months And not with the current price of over the R709. I it was vise verso you will not accept any excuses. Can you send me the recording of the telephone call of our conversation please? So when can you install my package at R649/m for 24 months with invoice number #INC-***?