How do I export Telegram contacts to my phone? I'm new here.

My little brother accidentally touched the "reset factory"  button in settings, and now I don't have my contacts on my phone! I have 1500 (almost 400 business) contacts with more than 670 profile pictures!

I rooted my phone and used recovery tools in W7, but nothing worked for me! I just recovered 10 old contacts, so God bless the Telegram app because I saw my contacts there,  but there are no contacts in my phone app. Is there any way to import contacts from the Telegram app to my phone app?

If possible please tell me how to fix this issue. Any guidance also in programming issues like linux terminals will be accepted in my way.

(Note: I used search in this site but there was nothing for my issue,
just found a link that a buddy wrote there:


  "Just install a contact backup software from google store like "+contact backup" and after that make a back up from your contacts." 


But there's no app in the app store with that name!
Just go to your accounts menu and select telegram\ accounts and then tap the current account and turn on Sync contacts. This way you can have all your contacts whom they have an telegram account.