iCloud contacts disappeared from iPhone

Suddenly, my contacts disappeared from my iPhone. Except 3 AND a unknown (new) contact "Ma Mavn" with a telephone number beginning with +84 (Vietnam). I don't have contacts in Vietnam.
My contacts where stored in my iCloud account.
When i went to my contacts in the iCloud website, i saw my contacts for a fraction of a second and then they where gone too.

I also have the contacts on my iPad, iMac and Macbook at home.
I'am afraid that my iPad is also synchronized but what should i do to avoid them to be removed from my iMac and Macbook.
Disconnect from internet? and then what?