Unfortunately, there isn’t anything that can be done until the Devs decide to unlock the server. And no Devs come here, so your pleas will be unheard.
You can keep an eye on this thread, they’ll update it when they decide to start unlocking things. But this is how it’s been since before WotLKC pre-patched, and I’ve yet to see any exceptions given. That’s why there is the confirmation box where you have to type “DELETE” before it’ll let you delete. Mistakes happen, but there are often consequences to those mistakes. This consequence is you’re now locked out of Grobb if you have no other live characters on that realm.
That is your right, of course. Again - you did the thing, no one else. And it will be you having to pay back that chargeback if/when you want to try and come back. I will warn you though? I’ve been seeing more cases of people’s debit/cards being invalidated to pay back said chargebacks; they’re requiring people to go out and buy Blizzard cards to apply money to their Blizzard Balance to pay back the chargeback.