Credit card charged by Amazon for unknown charges

I recently noticed some obscure Amazon chargebacks on my credit card statement, but when I went through the past few months of statements, I found several hundred dollars in charges that were deducted, my store is set up to deduct from my balance, and my account balance has always been sufficiently healthy.

There are several types of chargeback parties:

1. Amazon seller repay AMZN.com/BILLUS

This can be found on the report form.

These two have the same name but Amazon says they can't be traced.What should we do in these situations?