在生活中，我们难免会遇到一些不如意的事情，比如购买的商品质量不佳或服务不到位等。当这些问题影响到我们的生活时，写一封投诉信是一种有效的方式，既能够表达自己的不满，也能促使商家改进问题。以下是一封英语投诉信的格式范文，供参考：

[Your Name]

[Your Address]

[City, Postal Code]

[Email Address]

[Date]

[Recipient's Name]

[Company Name]

[Company Address]

[City, Postal Code]

Dear Sir/Madam,

I am writing to express my dissatisfaction with the recent purchase I made from your store. On [specific date], I purchased [describe the product or service], but unfortunately, it did not meet my expectations.

Firstly, the quality of the product was far below what I expected. [Describe specific issues with the product or service]. This has caused me significant inconvenience as [explain how it affected you].

Secondly, the customer service experience during this process was also disappointing. When I contacted your customer service team to address these concerns, I found that [describe any negative experiences with customer service, such as long wait times or unhelpful responses].

I believe that this situation could have been handled better, and I hope that you will take immediate action to resolve this matter. I would appreciate it if you could either replace the defective product or provide a full refund for my purchase. Additionally, I would like to request an improvement in the quality control measures to prevent similar issues from occurring in the future.

Thank you for taking the time to read my letter. I trust that you will address my concerns promptly and professionally. Please feel free to contact me at [your phone number or email address] should you require any further information.

Yours sincerely,

[Your Name]

这封信件简洁明了地表达了投诉者的不满，并提出了具体的解决方案。在撰写类似的投诉信时，建议保持礼貌和客观，这样更容易引起对方的重视并获得积极的回应。希望以上范文能对你有所帮助！