Usually, it's a syncing problem. Contacts can sync from many accounts on your device. When you sync your contacts to iCloud, Gmail, Yahoo, or other cloud services it means there are several copies of your contacts list.
Why do my contacts come back after I delete them?
webworkings : If you have the phone 'synced' to a google account, then your contacts are being backed up there. So when you delete them on the phone, it is readding them from the synced data. You would have to delete the contacts in that account (or whatever online account saved to) as well to stop this.
How do I permanently delete contacts from my phone?
On your Android phone or tablet, open the Contacts app . Select an option.
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Delete contacts
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Delete contacts
- Single contact: Tap the contact Delete forever. Delete forever.
- Multiple contacts: Touch and hold a contact and then tap the other contacts. Tap More Delete forever Delete forever.
- All contacts: Tap Empty Trash now. Delete forever.
