Resolved questions
誠に勝手ながら、の使い方を教えてください！

誠に勝手ながら = (directly translating ... ) without approval from users or those who enjoy some services

But, those are just pretty words. The company offering the services does not always think that they need to gain some approval.

誠に勝手ながら本サービスはyyyy年mm月dd日をもちまして、終了させていただきます（or ました）。
I am sorry to inform you that our service will terminate (or terminated) on dd/mm/yyy.