1. Check the purchase record: make sure that the customized clothing backpack has been purchased successfully and there is no payment problem. Check your purchase record to confirm whether the payment has been completed.

2. Log in to the game again: Sometimes, logging in to the game again can solve some display problems. Quit the game and log in again to see if you can find a customized clothing backpack.

3. Check the backpack classification: Make sure you are looking for customized clothing backpacks in the correct backpack classification. Sometimes, the items in the game will be classified into specific backpacks and may need to be found in different classifications.

4. Contact game customer service: If the above methods have not solved the problem, I suggest you contact QQ Xuanwu's customer service team. They will be able to provide more specific help and support to solve your problems.