Remove recyclerview items from activity

I am looking for android developer to help with my code. I have trouble with removing the item from the adapter when I am using the main activity. When I click on the delete button in the toolbar, I want to remove the item from the recyclerview when I am using the main activity. The freelancer I hired did not use the correct code. I want you to have a look on my code to see if you can fix it. I will pay $40 after the problem is resolved. I look forward to work with you.