Should I just use Phoenix for my use-case?

I want to build a system for a cruise selling agency in order to make proposals and invoices in a centralized manner. I will need to have 3 roles basically, client, seller, admin. I want to centralize the generation of such proposals, and also allow the notification to the client via various channels (mail initially)

I also want to feed product info into proposals, and will need to add on that later