Missing items and poor service

I made order for several items ,upon delivery two Items were missing, one was replaced with something I didn't order ,I've been enquiring about the other missing item and I've been sent from pillar to post , I'm not getting a real response everytime I asked I'm told to answer same questions, as if they are playing a delaying game for me to give up. I'm very disappointed. Its the end of the year now and they seem to be rushing things and that is costing us a lot .