I would say lift a corner and see if the underlay or backing is damp , if so float the carpet with the dryer beneath the corner .
It could take a couple of days to dry right . If it's just an odor in the customers head you might be in a situation you can't win , then sometimes they don't want the noise and disruption big dryers left on for long periods etc .. the only time I replaced a carpet was in a situation like that , I could have dryed it eventually but I was almost glad to resolve it the quick way to stop her calling me and the time wasted involved , plus the risk of a bad review ..going luck