I’d recommend taking a few steps before doing a chargeback in cases like this:

1. Search around for back channel support. Google things like “executive customer support”. Often times these emails get published by bloggers, forums, etc.

You can also look up support VP /Director’s names and then guess their email (e.g. first.last@example.com) and tell them your story.

2. Send a signature-required letter detailing out the issue, steps taken, and your requested resolution

These two steps get you significantly closer to having a person who can actually solve your problem actually look into the issue.