grammar errors in this paragraph

[thomas615]

Hello

I have not received a response from Mary to my letter I sent to her a month ago. I have called her telephone number many times for the past several weeks but that number keeps ringing and there has not been noone picking up the call. I believe Mary has moved to a new address.

Thank you

[I'm With Stupid]

Hello

I have not received a response from Mary to my letter I sent to her a month ago.[1] I have called her telephone number[2] many times for the past several weeks[3] but that number keeps ringing and there has not been noone picking up the call.[4] I believe Mary has moved to a new address.

Thank you

[1] You can either write:
"I have not received a response from Mary to my letter." or
"I have not received a response from Mary to the letter I sent to her a month ago."

[2] There's no need for "number" here.

[3] "many times in the past few weeks." If it's more than a few weeks, you would tend to say the exact number instead. So, "many times in the past 6 weeks."


[4] "there has been no-one picking up the phone." There is no need for the not, because you've already created the negative form by using no-one.

Also, you can use pick up the phone, answer the call or answer the phone, but not pick up the call.

So overall:
I have not received a response from Mary to the letter I sent to her a month ago. I have called her telephone many times in the past few weeks but that number keeps ringing and there has been noone picking up the phone. I believe Mary has moved to a new address.

Pretty good all around.