Missing Goods

We went to the Mall@reds branch to take out our media player, we paid the total amount repayable, but before signing we asked if it could be tested before going home.Upon testing it ,it showed no hard drive present, the salesman then opened the media player and found that the 2tb 2.5 hard drive was missing.The item has been there since (February/March) 2015 and the person that took it in is no longer working there.So what happened to the item? no one can explain or wants to take responsibility.We've been supporting that branch for years now,the sales people even know us by name.We have given them alot of support and business and now we are being accused of lying.The owner including David was very rude and arrogant and not willing to come to a solution.The owner then said he can maybe get us a 1tb in a few days time if I show him proof that I bought 2tb drive, which i refused.Why must I settle for a 1tb instead of a 2tb, what about all our data that was lost and where must I look for a invoice that is more than 3 years old.He did'nt want to give me one of the drives in store and said we must pay 50% if we want it.I refused again and he said we'll see each other in court.