Help! iPhone 4S contacts lost re. iCloud

A friend of mine had an invitation on her iPhone 4S to use iCloud. She accepted and now all her contacts on the phone are gone!!
Please can some kind person tell me how to get them back for her. First of all it just left the numbers on the phone and then they disappeared!
I don’t use Apple so I’ve no idea how to help her. Many thanks as always

iTunes restore to last backup?

Not really sure I don’t use itunes but I have a recollection of doing similar in the distant past for my daughter

Contacts —> Groups (Top Left Corner) –> Check iCloud is ticked.

Try Settings -> iCloud and check Contacts is ON. Also check that she is “logged in” to the iCloud using the email address she registered with. Bit of a guess as I’ve never had any trouble but that’s my setting.

As per Drac’s instructions but you can also select All Contacts

Sorry guys but I’m still having no luck. Drac, your instructions – are they for the iphone or icloud?
Can I set up the iphone to recover or reset to yesterdays info?