I understand your pain and frustration. The penalty for non-compliance with the name-matching policy does seem unnecessarily stiff. Something more along the lines of the reschedule fee would seem more appropriate. If your name matches according to the rules, you can appeal the decision. Please see this thread for an earlier discussion. Amanda's suggestion is a good one, send a (redacted) copy of your ID to (ISC)² and have them update the records to match according to their rules before attempting the exam again.
Unfortunately, cheaters have made it necessary for (ISC)² and PearsonVue to positively verify that the person taking the test is the same as the person getting the credit. Part of that is matching names with government IDs. (ISC)² is not alone in this. I have encountered similar issues at airports, renewing my driver's license and even once picking up my paycheck -- all because my last name has a space in it, which causes all sorts of filing, parsing and matching errors.
In today's world, there is value in ensuring that all your government documents match perfectly and that in certain other situations, such as this one, you are careful to use your "legal" name. If nothing else, it makes it easier to get through airport security, which is a goal we can all share.
In the name-matching policy (https://www.isc2.org/Register-for-Exam), you will find "Name changes cannot be made on your test day, including at the test center. If your names don’t match, you’ll be asked to leave. You’ll also forfeit your testing fee.".
This is why I suggested that if your name does in fact match (e.g. it was the test-proctor's error, not yours) that you might appeal the results. It is also why @Kaity suggested that you contact member services because it sounds as if you might have a case for an exception to the rule. Do be aware that contacting them works best by telephone and during Florida business hours (08:00-17:00 US-EST).
I've confirmed that your case is being worked on by our HQ and APAC teams - we'll reach out directly with an update @Mlugani