Call to WCF is not mocking

[Isolated]
        public void ValidateCustomerPolicyNumberTest(string zipcode, string policyNumber, string policyType, bool mockReturnValue, bool expectedValue)
        {
            bool actualValue;

            var fakeWcfService = Isolate.Fake.Instance<CustomerPolicyDataClient>();
            Isolate.WhenCalled(() => fakeWcfService.ValidateCustomerPolicyExists(zipcode, policyNumber)).WillReturn(mockReturnValue);
            Isolate.Swap.NextInstance<CustomerPolicyDataClient>().With(fakeWcfService);

            actualValue = CustomerPolicy.ValidateCustomerPolicyNumber(zipcode, policyNumber, policyType);

            Assert.AreEqual(expectedValue, actualValue);
        }


public static class CustomerPolicy
    {

        public static bool ValidateCustomerPolicyNumber(string zipCode, string policyNumber, string policyType)
        {
            bool isValid = false;
            PolicyTypes policyTypes = new PolicyTypes();

            if (policyTypes.ValidatePolicyType(policyNumber, policyType))
            {
                CustomerPolicyDataClient client = new CustomerPolicyDataClient();

                isValid = client.ValidateCustomerPolicyExists(zipCode, policyNumber);
            }

            return isValid;
        }

        
    }