Malice and Spite is not my thing

Okay, this is my first complaint letter (or rather, email) ever. I'm not sugar and spice and everything nice but neither am I nasty and obnoxious. But when I've had enough, I really mean I've had enough. No testing of the waters or pushing the buttons. Especially when I'm already on the ledge. This is the exact complaint letter that I sent under the feedback section : (I know I sound damn rude in the below letter but srsly it wasn't too much of me to say something mean to staffs who don't give a fuck at all)

Hi, I've received a mail from Singapore Post requesting us for the correct invoice and to include details of goods descriptions and true value as the Customs Authority Of Belgium wish to verify it.
I've actually sent an email to custsvcs@singpost.com but the email couldn't get processed so I sent it to pickup@singpost.com as suggested by one of the staffs.Yet again, the email couldn't get processed and I received YET another AUTOMATED REPLY.
There's something seriously wrong with the arrangement. First, Singpost requested on the letter itself to send the email to custsvcs@singpost.com but yet it can't get processed so I called the hotline (which you guys promised would give the fastest response, yea it was fast enough but it wasn't even accurate at all) and they directed me to send it to another email address.
Can you understand the customer's frustrations? All we wanted to do was to send a parcel to our family members at Belgium but something cropped up, which I can totally understand, cos' shit does happen at times but this whole process is unbelievably time consuming . I hope you can do something better than just sending another automated reply.
I wouldn't even have give a damn if you did not demand a reply by 11 October 2010, which is 2 days away, and impose return charges when you return the parcel back here and expecting us to bear it. Not exactly impressive yea?
Afterall we paid 70 over dollars not expecting for this to happen. I believe the money that we spent to send the parcel would deserve us some efficiency and response from you all.
Thanks alot for your understanding.
Regards,
_________