Making complaints and replying to letters of complaint

For making complaints

Opening the letter
I am writing to complain about ...
I am sorry to tell you that ...
I am writing with reference to ...
Eplaining why you are dissatisfied
There seems to have been an error
There appears to be a mistake / a misunderstanding ("Оказывается ..." можно юзать когда глобалы сделали что-то неправильно)
Requesting action
I would be glad if you would look into the matter
Suggestion action
The best solution would be to ...
I'd like to suggest that ...

For replying to letters of complaint (or Letters of Apology)

Showing understanding and sympathy
I am very sorry to hear that ...
I am sorry that you were dissatisfied with ...
Apologising
I would like to aplogise for the inconvinience you suffered (the problems you experienced).
Please accept our sincere apologies
Indicating action
I have looked into the matter
I have checked with the staff involved
Offering compensation
To compensate you for the inconvinience, we would like to offer you ...
Ending the letter
Thank for bringing this matter to my attention.
Once again, my apologies for the inconvinience caused.
We very much regret the embarrassment (затруднение) / annoyance (досада, раздражение) you experienced.
I very much hope that you will continue to use our company in the future.

Useful expressions from examples
I would like to apolgize on behalf of Alpha company ... (от лица)
I showed them your letter and explaned how upset (огорчение) you were.
They now regret that they did not take corrective action

Useful language to making complaints

Opening the letter
I am writing to complain about ...
I am sorry to tell you that ...
I am writing to reference to ...
Explaining why you are dissatisfied
These seems to have been an error.
There appears to be a mistake / a misunderstanding.
Requesting action
I would be glad if you would look into the matter.
Suggesting action
The best solution would be to ...
I'd like to suggest that ...

To finish letters

If you require any additional information, please do not hesitate (feel free) to contact me.
If you have any further questions, please do not hesitate to contact me.

To finish notification letters
Sorry for the inconvenience caused
Apologies for the inconvenience this may cause.
Apologies for the inconvenience.

Suggesting | Changing | Confirming arrangements

arrangements - меры, мероприятия, планы

Suggesting arrangements
Could we meet on Wednesday 4 May? at 11 o'clock?
Would Thursday at 10 suit you?
Is 12:30 convinient for you? (formal)
How about Monday 10th (formal)

Changing arrangements
I'm afraid something's come up.
Unfortunately I won't be able to make our meeting.
I'm sorry but there's a problem here at the office.

Confirming arrangements
This is to confirm that we we'll meeting on Tuesday as we agreed.
I'd like ti confirm the schedule for my April trip as we arranged.