Getting "Not Interested" Return Mail, Need Advice

[James Danchus]

What's up, BP?!

Need some advice on my mailer campaign. I'm handwriting letters to a handful of D4D leads and recently I got some return mail telling me they are "not interested" and "take me off the list." The sales rep in me says to continue mailing them as usual until they call and talk to me over the phone, but I realize this might be a huge wast of time.

Simple question: What do you do?