Restore deleted contacts from Google account
Google is maintaining your contact backup for 30 days and you can restore your contacts back to any selected time.
Below are simpple steps to restore contacts on andriod or IOS phone as far as you are using google contact sync. you can check How to sync google contacts on iphone, how to migrate adnriod contacts to iphone and select specific contacts to display on iphone to use google contacts on iphone .
1> go to google contact homepage from desktop/laptop – Google contact (this is old portal)
2> login with google account which have your contacts
3> click on more button -> then click on restore contact
4> select custom period -> then select days to which you want to restore contact back and time.
5> click on restore button.
6> you can check changes on google contact page immediately but to sync it on your mobile it will take 15/20 min.