There are multiple contacts in outlook.
I recommend you to use Google's Contacts.
It automatically finds your repeated contacts
And asks if you wish to join them.
It also recommends Vietnam code change
And changes in your contacts.
However Hotmail stayed long years ago.
Since I used my outlook adress as my Apple ID account, many of my contacts from outlook were repeated. Many of them are repeated hundreds of times. I tried to delete them, but I only can select 50 at once... so it becomes a very heavy job, because some of them have like 900 repetitions. What can I do?