A warning that you may run into while working with Walmart is Warning: UNPUBLISHED, 'UNDER_PERFORMING_SKU'.
If you are seeing this warning, it is an internal message from Walmart and should be dealt with through their support channels. There is a Walmart article regarding this warning found here:
Following those steps and reaching out to Walmart support is the advised resolution. If you feel your item(s) was(were) removed under false pretenses, please reach out to Walmart support to dispute!
If you have any questions, you can reach out to support!