Admittedly, I have no first hand experience with VB, but most other airlines by now only issue vouchers in a situation like this. You may face a struggle to get a refund to your credit card.

It has been reported in other threads (i.a. KLM) that AMEX sides with the airline now and will refuse to process chargebacks - but give it a try; it may be your only change to get a monetary refund here and now.

Do report back how it all went, thx