The banwave was due to Watchover being detected, not due to reports.
I recommend you to not chargeback.
Charging back will make your Battle.net account marked as "fraudulent" and you will not be able to buy anything else on the account. You can still chargeback, especially if you don't plan to use the account for anything else.
With that said, I have heard stories of people in the HonorBuddy section chargeback blizzard in paypal with the "incomplete duration" reason, and have successfully got the money back. Since i don't have a permanent/steady source of income, I will be charging back and hoping for the best.