Can I turn off the water valve when the water meter is negative?

You can't. Property water shutoff valve can't solve the problem of negative water meter. The water supply company should make clear whether the water meter property right belongs to the user or the water supply company. If the property right belongs to the user, then the water supply company has no right to close the water valve. Users can only negotiate with the water supply company to solve the problem, that is, users bear the maintenance costs of water meters, and then settle the costs with the water supply company after maintenance.