1‘you should ensure that complaints are handled speedily’
rapidly, swiftly, quickly, fast, post-haste, at speed, at full speed, at the speed of light, at full tilt, as fast as one's legs can carry one, at a gallop
promptly, immediately, briskly
hastily, hurriedly, precipitately
informal double quick, at a lick, hell for leather, pronto, at the double, a mile a minute, like the wind, like a bomb, at warp speed, like a bat out of hell, like a scalded cat, like the deuce, like nobody's business, like lightning, like greased lightning, like a madman, like a madwoman
British informal like the clappers, at a rate of knots, like billy-o
North American informal lickety-split
We take a look at several popular, though confusing, punctuation marks.