I want to send a letter to a company (specifically Microsoft). I've read some things that say one should write "To whom it may concern". I really don't like this; it sounds pretentious. Other sources suggest writing "Dear Sirs" or "Dear Sir or Madam". I don't care for either of these because in the former case a woman could be reading the letter, and in the latter case my letter could be read by multiple people. "Dear Sirs or Madams" sounds ridiculous. "Dear Microsoft" is obviously laughable (and I'm very apposed to corporate person-hood, hah!).
I've never particularly cared for "Dear" as the beginning to a letter myself. I don't even know who I'm writing to. But what options do I have other than "Dear"?
What should I do?