Number overview
For 050-3133-5964, directories and social media carry user reports describing fiber-line switch sales in the name of NTT or a fiber-line support center (as of 2026-08-03). jpnumber registers it as a business calling itself a line-support center, with similar reports on Telnavi, tellows, and number-lookup articles.
Reported behavior
- Posing as NTT or a major-carrier affiliate to push a line switch
- Rushing contract changes with campaign or discount talk
- Continued pitching even after the line was reportedly cancelled
How to handle this call
Never agree by phone
A legitimate provider will offer written terms and time to consider. Do not consent on the spot.
Verify with your own provider
For any talk of construction or billing, contact your current provider's official desk yourself.
Cooling-off rule
Telecom telemarketing is covered by Japan's initial contract cancellation rule: you can cancel within 8 days of receiving the contract document.
Sources of the reports
The descriptions on this page are based on user reports posted to third-party phone-number directories (checked as of 2026-08-03). This site has not independently verified the caller, and nothing here identifies the caller definitively. The reporting sources we checked are:
- jpnumber: registered as a business calling itself a fiber-line support center
- Number-lookup articles via Hatena Bookmark: reports of NTT-branded fiber sales (April 2026)
- Telnavi and tellows: user reports of fiber-line solicitation
- Threads and Instagram: posts reporting the same calls
Where to report or get help
- Consumer Hotline: 188
- Police consultation line: #9110
- Ministry of Internal Affairs and Communications - Telecommunications Consumer Consultation Center: 03-5253-5900