WCF WSDL vs ASMX WSDL

Question

Good day. 

I'm Converting our webservice(asmx) to WCF, my problem is when I get the WSDL of WCF our application that is reading that WSDL is throwing me an error "the element 'http://tempuri.org/:GetData' is missing. but in the ASMX generated WSDL it works fine?

is there something i need to add in my configuration to solve this? is the generated WSDL of ASMX different from WSDL generated from WCF? how can i fix this? 

been trying to find a solution for this since monday... your help will be appreciated greatly