We regret to inform you that .....
We are sorry to tell you that...
We are sorry to say that...
Thanks a lot for telling me about this.
Thanks for bringing this to my attention.
I appreciate you bringing this matter to my attention.
I am very unhappy about the service they gave me.
I am extremely dissatisfied with the service I received.
I'm not happy with the service I recieved.
I'm writing to give you some details regarding....
I want to tell you about...
I'd like to tell you about...
I have a ton of experience in this area.
I have a considerable amount of experience in this area.
I have a lot of experience in this area.
I can't come to your party tomorrow.
I won't be able to come to your party tomorrow.
I will be unable to attend your party tomorrow.
How are you?
How's it going?
All of the above.
Please accept our apologies for...
Shouldn't have done that.
None of the above.