Writing: Unit 2: On the move

Which sentence is the most suitable way to begin a formal email of complaint?

The most suitable sentence to end a formal email of complaint is ..........

In a formal email of complaint, what should the paragraph just before the closing do?

'It didn't arrive on time.' The formal equivalent in an email of complaint is: It .......... to arrive on time.

'More than 30 minutes late.' The formal equivalent is: .......... 30 minutes late.

'Not an apology from anyone.' The formal equivalent is: At no time .......... an apology.

Please understand that I am vehemently .......... to travelling with your company again after the way I was treated.

If you think I'm not willing to take my complaint further, you are gravely .......... .

The information I received about flight departure times was wildly .........., so I missed my plane.

In a formal email of complaint, which technique makes the writing less direct and more formal?