Doubt regarding mail for demo test

I have a pH test on 30th August, and for that have received an email. With the unique invite code for a single test. Whereas my friends who have enrolled for the same test, have received a demo test mail with invite codes for 2 tests - pH test and tech test.
Please clear this.

did you logged in with the invite code . if yes is your microphone is supporting the requirements ?

i got the invite code for the demo test but haven’t got the invite code for the main test which is on 30th august. how will i be able to give the exam on the exam date ?