Frankly, why such sick situation presents on your iPhone 6 depends on what you have done with it. After you sync Gmail, Outlook contacts on your iPhone, there is no doubt that contacts would be copied so some phone numbers, emails and names will be recorded more than once. Even though iCloud is a reliable way to manage your iPhone contacts, the trouble of duplicate contacts also comes with it.
Thus, to merge duplicate contacts on iPhone is wise to get away from such sick situation. At this time, an app to remove these repeated contacts is a must, like iOS Transfer, besides merging the copied contacts one by one manually. iOS Transfer can be a handy contacts manager to export/import iPhone contacts, transfer them among iDevices, back up iPhone contacts as well as merge repeated contacts.
It plays significant role in both transferring your iOS contacts and merging replicate contacts on your iOS devices.
Download and install iOS Transfer on computer. Then, connect your iPhone to computer with USB cable.
Step 2 Combine Duplicate Phone Numbers
After the program recognizes your iPhone, you need to select "Contacts" on the left list to choose "De-duplicate" on the top so that your iPhone contacts would be scanned automatically.
Note: You should make sure that you've installed iTunes on your computer.
When the processing bar goes to 100%, the repeated contacts will be listed on the pop-up. There are ten duplicate contacts and four duplicate groups also shown on the interface. Then, click "Merge Selected" to clean up the duplicate.
Notes: Before merging the contacts, you will be asked to choose a match type on the top side, for instance, "Name, email or phone matched" is selected in this case.
Only with a computer, a USB cable, and iOS Transfer, can you clean up duplicate contacts on your iPhone. In the process of merging the repeated contacts, backing up iPhone contacts is also done with iOS Transfer simultaneously. Moreover, various iPhone data can also be managed with iOS Transfer, including music, photos, videos,etc.