Contacts duplicate & auto removal

[Aqibsh]

Hii
I don't understand how contacts are mke duplicates and also when its synchronize then some contacts will removed and some times they will back i don't understand how its going on,whts happening with mbl

[Phy]

1. Contacts
2. Menu
3. Filters
4. If you have synced the contacts from different sources, it could create duplicates.