SharePoint 2013 Timer- Remove user from SharePoint group not working

Question

I have written a SP2013 timer job, which should remove user from SharePoint group when triggered. Written below piece of code in CustomTimerJob.cs. It updates the list item status to Active/Expired successfully on running the timer, but doesn't remove user from SharePoint group. Can let me know where I am wrong ?

 

using Microsoft.SharePoint;

using Microsoft.SharePoint.Administration;

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

namespace TimerJobApplication

{
public class CustomTimerJob : SPJobDefinition
 {
     public CustomTimerJob() : base() { }
     public CustomTimerJob(string jobName, SPService service)
         : base(jobName, service, null, SPJobLockType.None)
     {
         this.Title = "Access Rights Timer";
     }
     public CustomTimerJob(string jobName, SPWebApplication webapp)
         : base(jobName, webapp, null, SPJobLockType.ContentDatabase)
     {
         this.Title = "Access Rights Timer";
     }

     public void RemoveUser(String userLoginName, string groupName, string SiteURL)
     {
         SPSecurity.RunWithElevatedPrivileges(delegate()
         {
             using (SPSite site = new SPSite(SiteURL))
             {
                 using (SPWeb web = site.OpenWeb())
                 {
                     SPGroup group = web.SiteGroups[groupName];
                     SPUser userToRemove = web.EnsureUser(userLoginName);
                     group.RemoveUser(userToRemove);
                     group.Update();
                 }
             }
         });
     }

     public override void Execute(Guid targetInstanceId)
     {
         var currentdate=DateTime.Now.Date;
         SPWebApplication webApp = this.Parent as SPWebApplication;
         SPList taskList = webApp.Sites[0].AllWebs["dev"].Lists["Limited_Access_To_Security_Groups"];
         SPView view = taskList.Views["All Items"];   //custom view name
         SPListItemCollection olistitems = taskList.GetItems(view);
         foreach (SPListItem item in olistitems)
         {
             if (Convert.ToDateTime(item["ExpiryDate"]) <= DateTime.Now.Date)
             {
                RemoveUser(item["UserName"].ToString(), "Dev Visitors", "http://devsite/");
                 item["Status"] = "Expired";
                 item.Update();

             }
             else
             {
                 item["Status"] = "Active";
                 item.Update();

             }
         }
     }
 }