What exactly is this voucher good for?

They are being very convoluted (big surprise).

Where and when can I use this voucher?

What airlines can I use this voucher with?

I was suppose to fly to Treasure Cay in 5 weeks; I need to know now if I need to book with another airline or will this so called "voucher" be of any use.

I've sent numerous emails and made countless phone calls, nobody answers or responds back (another big surprise).

I've already filed a dispute with Visa; I paid for a service that I will not receive.

This "voucher" is an unacceptable fix.