Dear (No Number),
Please stop calling me and failing to leave a message for me. I do not answer my phone if:
A. There is no number. Or
2. I do not know the number.
Next time you would like to talk to me, please leave a message. I will not know who you are otherwise.
Thanking you in advance,
TRP.
PS. Calling 4 times today and not leaving one message is priceless to you, annoying to me.