Poor service and fault product

I bought a Xbox from Cash Crusaders Middestad in Bellville in December and within a few days it gave me problems and I took it to them for repairs, it was signed in for repairs in 21 December 2018 and now it is the 18th of March 2019 and I am still waiting for it, every time I go to check on it I am always told that it has not returned from repairs. I am tired of waiting because I only had it for a few days and now it's been almost 3 months since they had , I feel like I have wasted my money and I am so disappointed with their service