What list are you sending your yellow letters to?
Without this information, it is hard to advise. For example, if you are mailing to people going through divorce, they are usually far more defensive than someone in post bankruptcy or someone with an expired listing.
In general, when you get a seller on the phone you can say something like; “I am looking to buy a home in your area so I sent out letters to everyone over there. Thanks for calling me back. Are you interested in selling your house?” Be very kind and gentle, because you never know what they are dealing with.
You can overcome a whole lot of defensiveness in yellow letter sellers by being open when you talk to them. If they are motiviated, you can win them over. If they are not motivated, or will not share, then put them on an email follow up list (which is free), and determine if you think it is worth continuing to send them letters.
