On the website when booking, you have the option to book the cabin only, or the cabin with drinks, etc. since I hardly drink I book the bare bones cabin. Your TA might have booked that option. You should be able to access your reservation both in the app and on the website. I assume you got a confirmation from the TA, and you might also have one direct from MSC. If so, check to make sure the booking # matches.
On the website you can click on the person icon in the upper right menu bar to login. That gives you the option to log in using booking number, or to log in with username. Logging in with username should bring up a page with your cruise on it and it will show the correct booking number. Here are some screen shots showing the steps in order. When your booking number is correct you should be able to log into the app. (the app works fine on my iPhone and iPad mini, but won’t load on the full iPad).