received 50 dollar prepaid american express from rewards..certified $5.65 they paid. letter adressed from one name, address in dallas tx. tried to call to see why..not listed. american express said it is prepaid and would look into it. rewards gave me a womans name, address, phone in illinois. i called & wrote..no answer. you get rewards when you buy something. i did not buy and am afraid to use as it might commit me to something. nothing in letter except here is your reward. ?????? know anything re: it???