Lava Mobiles — unable to view my contacts

Sir.
Recently i purchase lava z60

The problem which i face is that i am not able to view my contacts that were in my sim... But now when someones calls me his name appears but after picking the call the names vanishhes and doesn't appear...in the call list as well... Plz suggest how to overcome thia problem...
With regards
Javid
Email: [protected]@gmail.com