your fats were not as wide as you expected but odds are that they are correct.
fat quarters are 18" by the width of the fabric.
if the fabric was only 40" wide, your fat quarters would be 18 x 20
if the fabric was wider but they trimmed off the selvages, it could still be "only" 18 x 20 but correct.
since most quilting fabrics are between 40 and 44 inches wide, if a fat quarter is properly cut to 18" high, it will average between 20 and 22 inches wide.
TO REPEAT: your fats were not as wide as you expected but odds are that they are correct.