Writing formal emails

You know the name
 Dear Mr Thompson, Dear Mrs Tucker, etc.
You don’t know the name
 Dear Sir or Madam,
Stating your aim
 I am writing in order to + inf
Answering
 I am writing with regard to … / I am writing with reference to … / I am
writing in response to …
 In reply to your letter of 8th June, …
 Could you tell me … ?
 I would be interested in having more details about …
 I would like information on …
 I would like to know if/when …
 I would like to complain about + noun / v-ing
 … is not what I expected / was expecting
 I am not satisfied with …
 I would be grateful if you could give me a refund …
 I would like to apologize on behalf of our Company.
 Please accept my sincere apologies for …
 Please allow me to apologize for …
 We appreciate that this caused you inconvenience…
 We see that our actions impacted you unnecessarily …
 We are convinced that the changes we have implemented will prevent this
from happening again.
 We will be increasing our efforts when it comes to…, so that in the future…
 We have increased our efforts to ensure that…
 I can promise you that the highest quality standards will be met going
forward.
 We could + inf …
 I thought we might + inf …
 I suggest we + present simple …
 It might be a good idea to + inf …
 I look forward to hearing from you soon / to receiving your reply
 I would like to thank you in advance for this information.
 Should you need further information, please do not hesitate to contact
me.
 Yours sincerely,
(Name)
 Yours faithfully,
(Name)