The performance of wireless charging depends on many factors, including the wireless charger and receiver that you use. The MobilePal wireless power bank has been fine tuned to work with a wide range of wireless receivers, but there are many variations of the receivers, so there may be some exceptions. 

In addition, the performance depends on whether the center of the phone is properly aligned with that of the wireless transmitter. On a number of phone models, the wireless receiver is not at the center of the phone (such as Google Nexus 6). Initially, it may take some trial and error to find the sweet spot for charging. 

If you believe the product is defective after troubleshooting, please contact MobilePal customer care so that we can refund or replace the product for you.