If you payed for the Pre-Release and did not get access to any of the Pre-Release content then you should be due a Refund. To get a Refund for the difference that you paid for the Pre-Release version VS the regular release is all that you might be able to recover.
To start that process you should contact SE support directly and try to have your Proof of Purchase with you.
Don't listen to these guys who say you are not entitled to a refund because they don't know what they are talking about. If you pay for a service and you do not receive that service then you should ask for a Refund of that service.