1. Service registrations that share data for marketing. 2. Data brokers who buy and sell customer lists. 3. Random dialing systems that call numbers sequentially. 4. Your number posted on social media or websites. 5. Data breaches at companies you've used.
Minimize sharing your number, use spam-blocking apps, let unknown calls go to voicemail, and clearly tell telemarketers to stop calling.
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Yes. Under Japan's Personal Information Protection Act, you have the right to ask. Companies that refuse to answer may be using illegally obtained data.
Temporarily, yes. But your new number can leak again through service registrations. Anti-spam apps and call blocking are more practical long-term solutions.
There's no direct way to check, but you can infer it. If you frequently receive sales calls matching your demographics (age, occupation, area), an attributed list is likely circulating. You can consult the Personal Information Protection Commission, which may investigate data brokers.
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