You can communicate with the Help Desk staff via message
or by phone:

For guidance information

every day from Monday to Friday
from 3 PM to 5 PM.

For technical assistance and support on the test day:

Monday (ONLY for those who have the test on Tuesday)
from 10 AM to 1 PM and from 2 PM to 5 PM. From Tuesday to Friday,
from 8:45 AM to 1 PM and from 2 PM to 5:30 PM.

When you call for test assistance, remember to have the TEST CODE with you, which you can find on the Payment and Enrolment Receipt.