Unconditional Offer in the applicant portal but no official email

Not super unusual, but would contact them after 5 working days since UCAS updated.

I would call rather than email. Emails can go unanswered for weeks at various stages of the application cycle. A call should give you an immediate answer.

NB. The offer in UCAS is binding, even if it was an error, (it's very unlikely to be).

I´m an international student applying for a Masters degree at Goldsmiths University London. Last monday I logged in to the applicant portal to check my application status and I found out that an unconditional offer had been made on my application; which I proceeded to accept; but I didn´t receive an official email with the offer letter nor any further information, and haven´t received it yet.
I´m a little bit worried about this, and I´ve been wondering if this could´ve been some kind of mistake... Can anyone give me some insight/advice on what to do in this situation or why could this sort of things happen?
Thank you!