WCF Errors

The type 'TransactionService.TransactionInfo', provided as the Service attribute value in the ServiceHost directive, or provided in the configuration element system.serviceModel/serviceHostingEnvironment/serviceActivations could not be found.

I changed the output path of the service. it should be inside bin folder of the service project. Once I put the output path back to bin, it worked.

WCF - Contract Name could not be found in the list of contracts

Your contract is the Interface not the implementation.Somewhere in the config you have written myService instead of IJsonService.