Facebook plaugin serious problem

Hi,

this happened to me before maybe one month ago, but now it happened again for another page that is way more important, and it’s already doing damage to my traffic.

I have a wordpress post with maybe 30 facebook comments in it using a facebook comments plugin .. One day all the comments dissappeared, and the count went back to zero ..

the other pages / posts in the blog are ok, only one specific page had the comments dissapearing ..

I did not change anything in the URL, the facebook likes number is the same , just the comments dissapeared ..

any idea on how to start and where to look to fix this ?

Please advise this is really important

thank you