When Bob has a problem with Ann's scummy business Bob should ask Bob's credit card company for a refund, which generates chargebacks for Ann's business.
For me, not having to deal with a vendor (or even its credit card company) is a major advantage of using a credit card instead – for example – paying by invoice.
I have just checked my credit card issuer's process for such cases, it seems pretty straight forward.
The down vote of my comment indicates a possible difference in other parts of the world …
When Bob has a problem with Ann's scummy business Bob should ask Bob's credit card company for a refund, which generates chargebacks for Ann's business.