Is ur Samsung or Google account in any other phone also? I had this problem , i and my relative had the same contacts list and it got synced. So he deleted some of my contacts and it got deleted in my phone also.
And for that , i had to manually save my contacts in my other acc which is not linked to any of them . For that , whenever u save a contact , while editing it , u will see a pop-up on the above , choose the acc which u feel the best, u can choose ur number as the storage for contacts too i guess.
