Failing to order

I purchased door handles at Builders Superstore in Alexandra on the 15 of November 2018 for my Kitchen units designed by a company called UCAN. The store manager told me they don't have stock but they will let me know when they do, so that i can collect them as i have already paid for them. The guys from UCAN tried contacting the store to order my handles so that they can have my kitchen units installed. But to this day, i still have not received the handles as builders have not orderd them. Why must a customer go through such trouble just to have handles orderd whereas i have already paid for them. Maybe Builders should just give me the order sheet and i just order them myself, and builders starts paying me cause clearly somone is not doing their job, so i will do it.