You should be able to make an instance of ShopWCFClient and then just call the methods on it that are on your web service.
ShopWCFClient client = new ShopWCFClient();
var myData = client.GetData();
I use an online web service like this for a WP7 app that I have and it works quite well. I can send you samples later if you want or can help you if you give me the address of the web service.