The later it gets in the fall, the harder it is going to be to pinpoint the bears. Since food sources are becoming scarce (berries are bye bye), bears are less concentrated. However, they are looking for food all the time bout now, fattening up for winter.
Dont get frustrated. It takes time to lock down bears sometimes. Look for stumps that they could tear into....any left over berry patches (there are still some around)...etc.
Keep calling, that might be a good bet for you this time of year. Keep at it. You'll never find one sitting in the house.

Good luck!