I sense your frustration, but the problems that you've described would be best served by communicating directly with Support.
Don't know how many support tickets you've sent in, but do try again.
Fusion Cash is a reliable organization. If they can help you, they will.
If, however, the credits you've lost are due to advertisers reversing the credits, then FC will not be able to help. If they don't get paid, they can't pay you.
If the problem is just a system glitch, it will work itself out and the credits will come back in due time.
In the meanwhile, keep doing Radio Loyalty, the videos and the daily click and post daily on the Forum to work toward the monthly Forum posting bonus.
Oh, another thing: you can't cancel you account. Oops! I'm wrong - see below.
You can walk away from it, if you want, but it will only become an inactive account. Not sure whether it becomes inaccessible after a time. Never had a reason to test that.
Ladavia89 is correct that you CAN cancel your account. There is a link in the Terms of Service if you still want to do this:
""Cancellation/Deletion. If you wish to "cancel" or "delete" your account, you may do so by clicking here (login required). Note that deactivated accounts are not recoverable under any circumstances, and you may not create another account at any point after deactivation. "