OK, first of all, you need to be 13+ to use this site because Anthony and his contributors have a habit of resorting to unparliamentary language (1) from time to time. That’s what happens when you’re angry so don’t act surprised if the odd bad word turns up now and then!
Sexual content is unlikely, mainly because people who write letters of complaint to service providers in that sector are unlikely to share them with Dear Customer Relations (though they would no doubt be very interesting letters indeed).
The companies or organisations who are in receipt of letters reproduced on the Dear Customer Relations site are free to ask nicely to have them removed from the site or have their real identity changed (the latter being encouraged as it still allows readers to enjoy the letters but still spares your blushes). Your wishes will usually be respected. However, some say that there is no such thing as bad publicity so if I was you, I’d grin and bear it. Better still, reply to the letter with good grace and humour and Dear Customer Relations will ensure that your reply is included on the site.
Similarly, those who kindly contribute their own letters to Dear Customer Relations can ask to have their names changed or not as the case may be (DCR will point out that a false name has been used however). They should also decide before submitting a letter whether they wish to use the name of the actual recipient company/organisation or substitite a fictional one (see Snooty Manor Hotel, Nether Scrotum for one such example).
By contributing a letter for the Dear Customer Relations site, authors agree to grant a perpetual, royalty-free license to Dear Customer Realtions to reproduce and publish the letter. They also agree to allow Dear Customer Relations to edit the letter to make it suitable for inclusion. That editing may be of syntax, setting out, length or content but we will generally try to minimise changes and preserve the original character of the letter. For the most part, letters are not edited at all.
One important thing – the subject matter of the complaint must relate to a genuine experience. If Dear Customer Relations suspects that the letter is a work of fiction, then the letter will not be used (unless it is especially funny in which case we’ll point out that isn’t genuine). Similarly, the letter must have a light-hearted or tongue-in-cheek style which affords the recipient the opportunity to respond in kind if he so chooses. Nasty, abusive letters will not be used (though very funny, slightly abusive letters may be considered).
Where letters are included in the ‘Best Ever’ pages, Dear Customer Relations will attempt to obtain the permission of the author but this is not always possible. If you can demonstrate that you are the original author of any letter reproduced on Dear Customer Relations and you wish to have the letter removed, we will immediately comply with any such request.
Dear Customer Relations will never share personal information of any kind with any third party. The names of contributors will be used when so agreed with the contributor but their email addresses and any other personal information provided to Dear Customer Relations will remain private at all times.
Nearly all the letters have actually been sent and where replies were received, these are included. Where letters were not sent, this is made clear in the text.
I have added all the footnotes (2) so if they contain errors, distortions or insults, the fault is entirely mine.
 For the benefit of American readers, unparliamentary language is a reference to a peculiarity of our ancient system of democracy whereby our beloved Members of Parliament are not allowed to use naughty words when within the confines of ‘The House’ (of Commons). It is perfectly allowable for them to fiddle their expenses and keep their mistresses in luxury apartments at the taxpayers’ expense but they are not allowed to be rude about each other. They are allowed to use words of public school origin such as ‘cad’ and ‘bounder’, but they are not allowed to call their colleagues ‘dickhead’ or ‘bastard’ (unparliamentary language) until they are outside. That is why the House of Commons terrace bar is so popular.
 Including this one!