Duplicate contacts and missing information after saving on iPhone

once it is saved, it shows up as saved for a few seconds, and then it goes back to maybe with the person’s name. Also when someone calls and it has their name and other contact info and pictures and I save that. A few seconds later, it’s all gone and it’s just a phone number. Then when I go and look for it, it’s gone, and when I save it a second time it appears twice in my contacts.

[Re-Titled by Moderator]

Original Title: every time i save a new contact, it doenst save. then when i go to save it again, it is in my contacts twice