WCF disable proxy creation for security

just read this link https://stackoverflow.com/questions/5671885/what-happens-if-i-set-httpgetenabled-false

1) tell me what i need to do disable proxy creation of wcf service ? do i need to remove mex endpoint from config file

<endpoint address="mex" binding="mexBasicHttpBinding" contract="IMetadataExchange"/>

and also need to set false to httpGetEnabled="false" ?

if i am right then how 3rd part client will be using my service ? what i need to give them as a result they should be able to call my service ?

How many service contact i can create in a single wcf service project ?

thanks