If a foreclosure plaintiff seeks not only to foreclose on the property but also to recover the remainder of the debt through a deficiency judgment, then the plaintiff is attempting to collect a debt within the meaning of the FDCPA. But if the plaintiff is simply enforcing a security interest by retaking or forcing a sale of the property, without regard to any additional debt that may be owed, then the plaintiff is not collecting a debt and the FDCPA does not apply.