WCF service Post error on IIS 6 - json

Question

I have developed a REST service that used to run localy on my PC and had no issues!!I have hosted my wcf on a windows server 2008-r2 IIS 7.5, in order to call my service from an IP. I am using the get method with a JSON and all works fine, but when i try the post( with chrome plugin) i get 405 error and 500 error. I checked the MIME-TYPES and added json for IIS. Any solution or suggestiong how to resolve this error would be very useful.
I will post my webconfig and ISERVICE files as well.
My webConfig file is as follows:
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<system.web>
<compilation targetFramework="4.0" />
</system.web>
<system.serviceModel>
<services>
<service name="RestService.RestServiceImpl" behaviorConfiguration="ServiceBehaviour">
<!-- Service Endpoints -->
<!-- Unless fully qualified, address is relative to base address supplied above -->
<endpoint address="" binding="webHttpBinding" contract="RestService.IRestServiceImpl" behaviorConfiguration="Services.webHttpBehavior">
<!--
Upon deployment, the following identity element should be removed or replaced to reflect the
identity under which the deployed service runs. If removed, WCF will infer an appropriate identity
automatically.
-->
</endpoint>
</service>
</services>
<behaviors>
<serviceBehaviors>
<behavior name="ServiceBehaviour">
<!-- To avoid disclosing metadata information, set the value below to false and remove the metadata endpoint above before deployment -->
<serviceMetadata httpGetEnabled="true" />
<!-- To receive exception details in faults for debugging purposes, set the value below to true. Set to false before deployment to avoid disclosing exception information -->
<serviceDebug includeExceptionDetailInFaults="false" />
</behavior>
</serviceBehaviors>
<endpointBehaviors>
<behavior name="web">
<webHttp/>
</behavior>
<behavior name="Services.webHttpBehavior">
<webHttp defaultOutgoingResponseFormat="Json" />
</behavior>
</endpointBehaviors>
</behaviors>
<serviceHostingEnvironment multipleSiteBindingsEnabled="true" />
<diagnostics>
<messageLogging logEntireMessage="true" logMalformedMessages="true" logMessagesAtServiceLevel="true" logMessagesAtTransportLevel="true" />
</diagnostics>
</system.serviceModel>
<system.webServer>
<modules runAllManagedModulesForAllRequests="true" />
<!-- <staticContent>
<mimeMap fileExtension=".json" mimeType="application/json"/>
</staticContent>-->
</system.webServer>
<system.diagnostics>
<sources>
<source name="System.ServiceModel" switchValue="Information, ActivityTracing" propagateActivity="true">
<listeners>
<add name="traceListener" type="System.Diagnostics.XmlWriterTraceListener" initializeData="C:\wcflog3.txt" />
</listeners>
</source>
</sources>
</system.diagnostics>
</configuration>
My Service Implementtion is as followes:
[OperationContract]
[WebInvoke(Method = "GET",
ResponseFormat = WebMessageFormat.Xml,
BodyStyle = WebMessageBodyStyle.Wrapped,
UriTemplate = "xml/{str}")]
string XMLData(string str);
[OperationContract]
[WebInvoke(Method = "POST",
ResponseFormat = WebMessageFormat.Json,
BodyStyle = WebMessageBodyStyle.Bare,
RequestFormat = WebMessageFormat.Json,
UriTemplate = "jsoncheckifexists")]
bool CheckIfExists(RestService.RestServiceImpl.UrlObject data);
The GET is working just fine, I try the POST calling the function CheckIfExists:
public bool CheckIfExists(UrlObject urlObject)
{
string link= urlObject.url;
//Standard logon to CRM procedure(Framework)
if abc=true
return true;
else false;
}