I don’t think I was ever contacted to set up my account. I only ever received the confirmation from the common app. Should I contact them to inquire? If so, who would I contact?
First, have you checked your spam inbox? Sometimes things do go there. You can call the admissions office if you legitimately didn’t get it.
Just go to https://apply.college.brown.edu/account/login, click “Forgot your password”, and follow the instructions to get a new PIN. My DS never received his portal email either, but setup the portal this way easily.