Complaint letter Letter

After reading 'Formal Business Writing: Resolving Difficult Commercial Situations' by Michael Chambers, I would like to write a letter to a shoes company, because I had a problem with one of their products. I don’t want to write a letter ‘too aggressively’. Could you help me to write a polite (and grammatically correct) complaint letter, please?

Dear Sirs, Dear Madam, To Whom It May Concern,

my My name is Andrea and I have been using xxx’s products since for a long time. I have used your products in different disciplines ways and I have always appreciated their comfort and technology, as well as the style.
I am writing to inform you about a defect I encountered on my last pair of running shoes. After a few months I was of using them, two eyelets broke and so it was became impossible to do up tie the shoes properly. I would like to point out, that when I was doing up tying the shoes, I wasn’t stretching the shoelace as stronger hard as I could. I have attached some pictures to allow you to analyze better the problem. the problem.
As a mechanical engineer, I know how important is to receive feedback, and I hope this could will help you to work out solve the problem. I hope also I also hope that I will not to have again the same problem again with my new shoes I have recently bought.

Your Sincerely,

Andrea

Not too bad Andrea, you did a nice job writing this letter, you just had a few grammar mistakes is all. I hope you find my corrections helpful. If you have any questions please feel free to ask, I'd be happy to help you improve your English!