iPhone 4 keeps losing contacts

I disconnected "Contacts" from iCloud. When I did this, the iPhone 4 asked if I wanted to "keep contacts on iPhone?" to which of course I answered "YES".

Now, for the second time in a month, I turn on my iPhone, go to "contacts" and it states "No Contacts". All 800+ contacts have disappeared. AGAIN.

Why is this happening?

I want to store my contacts on my iPhone. Period. I have them backed up in iTunes, but that is a real pain to have to keep goint back to restore them when this happens.

iPhone 4

OS 5.1.1

1.5 gig available (8 gig total)