Hello everybody,
I was wondering if I can begin a more or less formal letter the following way:
Dear....,
Unfortunately, I didn't get any reply from you to my letter last week. (I) hope everything is fine with you..
Thanks in advance for your comments!
I'm not quite clear on what you mean by "more or less formal". It's either a formal letter (to a company, the bank, a university etc) or it's not (to a friend, a relative etc).
I would say for formal:
"Dear Sir/Madam (or their name if you know it)
I have not received a response to my letter of last week. [From here, the main body of the letter. In a formal letter, I certainly wouldn't ask after the health of the recipient.]"
For informal:
"Dear [first name/forename]
I hope you're well. I wrote to you last week but I haven't heard back from you...."
Hope that helps.