Unrated players taking advantage of lower rated

My question is when i accepted a challenge this wesite proposed to me

this challenger was  UNRATED.. AFTER THE MATCH WAS OVER & I LOST

 i find out this challenger had a rating of 1395..

i check this person past matches he has & had a rating close to 1200

this website needs to clarify ALOT BETTER ,,THEIR RATING SYSTEM