Incorrect parts received and no resolution a month later

I bought a garden patio set online from Makro. It came as a flat pack which has to be assembled your self. The set consists of two single seats and one two seater and a coffee table. I assembled the single seats and coffee table and on starting the two seater I saw that they sent the wrong part. It had two right side arm rests / legs instead of one left and one right. There is no way that this seat can be assembled I immediately emailed Makro and had no response. I phone customer service a couple days later they insisted that they will get back to me and still nothing. I tried to phone the manager of the store it was delivered from but just get placed on hold and have not been able to get this matter resolved. Now I am sitting with half a patio set that cost me R3000. This is disgusting service and a complete lack of care for their customers.