Unfortunately I have three Adobe accounts. One for Adobe Sketch, One for a Fresco, to try it out, and one for Behance. I have been using Sketch for a number of years. I intially gave Fresco a try, but didn't initially like it. Recently I have been forced to switch to Fresco as Sketch is nolonger accessible. Unfortunately my Sketch files were not showing up in my Fresco account. In the meantime I added a premium subscription to this account. In oder to access my Sketch files I had to upgrade from within the Sketch account. When I did this I was able to import my Sketch files into my new Fresco account. Now I would like to add the Premium subscription to this account, but Adobe will not allow me to do so. It says that I already have an account with the Premium subscription. I canceled the Premium subscription on the old account,but unfortunately I still can not subscribe. I have spent the better part of the past week going back and forth with Adobe help centre and they are absolutely hopeless and have not been able to resolve this. It is quite unbelievable and shameful.
Responses on the forum are generally given by users of the apps, not staff. Our response in your case would actually have been to contact Adobe Care but it sounds like this hasn't been too beneficial to you. You could try sending an email directly to the Fresco Help team (frescohelp at adobe dot com) to see if they can assist you to transfer your files and regain the premium subscription.