What is the best way to handle phone syncing from contacts to app?

I need to sync iPhone contacts with app. We can store only 1 phone number and the contacts may have 2 or more. On top of that these phones are not labeled properly so I cannot filter them "sync only mobile phone number". How do you handle this scenario? Do you sync all phone numbers and store them in app? Thank you and if this question has been answered before please point me in the right direction.