Paramount+Premium

I’m trying to set up Paramount + Premium through T-Mobile but it is not going well.  The sign-up instructions seems to have gotten me an account but through Paramount not T-Mobile.  I contacted Paramount but they indicated I could not have Premium but I have the screenshot of my account saying I can, then we cannot figure out how to sign up correctly (I did have to cancel the subscription this morning).  Is there an easy way to fix this matter?