1. Please try with other different cables & charger plugs you have.
2. Remove the phone to charge the battery case separately, checking if it will be recharged.
3. Try to charge it with a wireless charger. If the battery case can be charged, then there should be something wrong with the charging port. Otherwise, the battery inside is defective.
If the problem still exists, we'd love to provide you a warranty replacement. Please send an e-mail to infor@zerolemon.com with your order number. Thanks.
Our response time is within 24 hours, except during the weekend.