outstanding order

I have ordered 10pc of curtains in august however i only receive 5pc then i was advised to complete dispute form, the consultant called me to say they will replace it and i will get SMS for delivery, till today nothing every time when i call i get different stories,i am really frustrated right now I'm even considering to hand the matter to ombudsman. I even check on line i see that there's a stock for my order why is it difficult for them to just replace my order