Creditor calls are to be expected. You are not obligated to speak to your creditors. There are many reasons we do not recommend speaking to creditors. Once they know they can contact you they will continue to contact you; they might not want to speak to a 3rd party if they can contact you directly. Also, keep in mind that creditors may use scare tactics such as telling you that they do not work with debt settlement companies. They may tell you they are willing to work with you to convince you to make a payment. Speaking with creditors will interfere with the negotiation process.
Some clients have gone as far as changing their phone number and you can also make sure your phone number is unlisted and unpublished.