Hello there Clau_Cotia,
Welcome to Apple Support Communities. Are your contacts synced to access a business or school directory? If so, this could have been set up as a cardDAV:
Set up an LDAP or CardDAV account to access business or school directories
1. Go to Settings
> Contacts > Accounts > Add Account, then tap Other.
2. Tap Add LDAP Account or Add CardDAV Account, then enter the account information.
From this page: Use other contact accounts on iPhone - Apple Support
If your iPhone is a managed device from a school or employer, check with your administrator or IT department for assistance.
This page can help you determine if you iPhone is managed or supervised:
Get started with a supervised iPhone, iPad, or iPod touch - Apple Support
Let us know if you have any questions.
Best regards!