Is the meter actually connected? If so, there may be a valve buried in the road outside. In our village, the Mairie had the key!
You need to phone or speak to someone face to face - only way to get things done in France ;-)
Write again but send by registered post and with an international acknowledgement of receipt required when they sign for it. A lot of French companies won't leap into action without receiving a lettre recommandé avec avis de reception. Advise them that you require a rendez-vous on site for the first week your partner will be in France.