How can I fix my whirlpool side by side fridge/free?

I have recently had the side by side fridge plumbed in at my new house (was operating fine 2 years ago when we moved from the old house)... the chill filtered water is coming through fine but I can't get the ice maker to work .... when we disconnected the skinny water pipe that goes at the back at the top of the fridge no water came out so i dont think any is being pumped from the bottom up to the freezer .. can anyone offer any suggestions.. im not too keen on the 80 dollar call out fee that the technician has quoted