In the Event that You need user imports V3/V4 to be stopped for a period of time, this can be done by disabling the service.
Doing this will also Stop the import Addresses from running, as well as the Import Price Pointers, though pointers will still run if a full price pull is done.
To Disable, go to Admin > Data Transfer > Service Configuration, find the most recent version of the service that has been enabled, i.e if you have v4 installed that is the one that should be enabled and disabled as needed, not V3.
Next click Edit, to now disable, untick the Enabled field, and save.
In the event it need re-enabling, simply edit, tick the setting and save.