POOR QUALITY STOCK

On 21/12/2015 I bought a acoustic guitar from Cash Crusaders Melville. The Guitar was NOT in use till February 2016 when my guitar lessons was going to start. Then I saw that the bridge/saddle completely pulled away for the guitar. They did not want to refund me on 05/02/2016 they insisted on repairs. Today 19/02/2016 I still did not get the repaired product. I would like to have a REFUND instead because when I bought it they promised me that they have not have comebacks on this product, but I think they **** to me in my face. Tonight I am going for my 3rd lesson which cost R100 for half an hour and I still haven't got a guitar to practice on. I have wasted my money!!! Please help to resolve this!!!!!