请给我一封适用于大多数情况的投诉信的大体框架. 内容包括:第一段:表达遗憾;第二段;说明问题;3.第三段:提出合理诉求;4.可适当增加词汇,使行文连贯; 5.字数不少于120字; 6.至少使用10句复合句或特殊句型. 7.多使用雅思和托福高级词汇 Please reply in English

Dear Sir/Madam,

I am writing to express my deep disappointment regarding a recent issue that I encountered with your company. I have been a loyal customer of your company for several years, and it pains me to have to write this letter.

The problem that I encountered was (describe the problem in detail). This has caused me a great deal of inconvenience and frustration, and I believe that this situation could have been avoided.

I would like to request that your company take immediate action to rectify the situation. Specifically, I would like (state your reasonable request here). I believe that this is a fair and reasonable request, and I hope that your company will take this matter seriously and address it promptly.

In conclusion, I would like to reiterate my disappointment with the situation and my hope that your company will take the necessary steps to resolve it. Thank you for your attention to this matter.

Sincerely,

[Your Name]