ACM either need to confirm your Registration/Attendance with Student Finance or Student Finance have not yet completed processing your application.
You can check your Student Finance online account to see if your loan has been approved.
Alternatively you can contact Student Finance England on 0300 100 0607. If you have a student loan from one of the other home countries, you can find their number on the gov.uk website https://www.gov.uk/guidance/guidance-on-contacting-the-student-loans-company (have your Customer Reference Number to hand) or contact the ACM Student Finance Team on 01483 500848 studentfinance@acm.ac.uk