Sorry to hear that your Huawei Mate40 wireless charging is faulty. To solve this problem, you can try the following steps:
1. Make sure there are no obstructions on the charging pad and the back of the phone.
2. Check that the charging pad and the phone support the same wireless charging standard.
3. Try using a different charging pad for charging.
4. Restart the phone and update the latest software version. If the problem persists, you are advised to contact Huawei customer service or go to an authorized maintenance center for further check and repair.