So was in the middle of a nightfall with my 2 friends and poof banned? No reason why nothing. I've never been banned from anything what is this?
If you feel you were truly banned unlawfully, do what BDO players did: charge back. Hopefully you used a credit card/debit card. A simple call/visit to your bank branch will get your money back easily if you are in good standing with them. You will never be allowed to purchase the product again, but if your situation is true, I'm sure you are not wanting to. Keep in mind that YOU are the customer, and in most markets you have all the power.