How can I merge duplicated contacts that are different only in one letter? I use "Contact Remover Plus" to merge duplicated contacts. But I want also merge contacts that their names are different just in a letter.

How can I merge these duplicated contacts? I am looking for a automatic solution.
Google Contacts is your best option. It will merge contacts with different names if things like their email addresses are the same. Also, if for some reason, it doesn't detect the contacts that should be merged, you can select multiple contacts manually and click on Merge Contacts from the more actions menu.