Warning about an extremely likely auひかり scam

Perhaps some of you may already be familiar with this but I'm sharing this for visibility and as a caution to others about this extremely likely scam.

I was visited late at night by someone from a 特約店 for auひかり. For the purpose of his visit, he stated the following:-
1. Residents at my apartment complained about slow internet speeds hence his visit
2. I didn't quite catch it clearly but they will either begin construction or had completed fiber construction work
3. If I change my internet provider to auひかり、they have a special plan whereas I will receive a 30万円 cashback plus the first 6 months subscription would be cheaper than my current provider at around 2千円
4. As for my part, I only have to sign the contract and setup a date for the router to be delivered by Amazon and installed by GMO

I was relatively suspicious at first but I was fooled by his formal presentation, i.e he had an official looking 名刺, pamphlet and documents plus he carried a tablet which featured an authentic application form. Additionally, my mobile carrier so happens to be KDDI and the offer sounded quite good.

Regrettably, I didn't corroborate the authenticity of his 名刺 and, in the end, on his tablet, I shared my name, date of birth, address and phone number plus I signed the 申込書 and on matters regarding compliance, i.e whether I understood what was being presented.

I should have done this at the time of his visit but today I did my due diligence and checked the information provided on his 名刺 and discovered it's a scam based on the negative 口コミ entries regarding said 特約店 that he represents and the address provided doesn't have any proper leads.

Thankfully I didn't share my bank account details nor sign any 口座振込手続き yet but I am expecting them to call to inquire about the date of delivery for the router, the installation plus more.

Many might point out that such a late night visit is an immediate red flag, but having just checked my intercom recordings, he visited me days prior in the early afternoon but I wasn't present. In other words, they could visit any time in the day.
The real red flag that I failed to pickup would be:-
1. KDDI would never visit your residence and would only communicate via email, phone or はがき
2. There would have been a 通知書 from either the ISP or アパート管理会社 regarding any fiber construction

Whilst I believe I am mostly safe as I haven't provided my account details, I intend to call the KDDI customer support for advice plus inform my アパート管理会社 about it tomorrow.

by Toki_day