How can a client stop their agency or Votel support from logging into their account?

The account owner turns on the disable access switch on the account's profile. When it is on, no one else can log in to the account: the agency cannot and support cannot. Only the account owner can, so the client must turn the switch on in their own account.

Other privacy controls: role based access controls let you set what each team member can see and do in each section, and you can mask personal information so users can see a contact but not its full details, for example only part of the name.