That was way back when it first came out, like 3 years ago? I dont have it anymore.
If you purcahsed the software from the forum store, the key should be located in the client area under "Purchases".
Did you make your purchase via Amazon.com? If so, you'll need to visit
https://www.amazon.com/YourGamesAndSoftware under the user that had made the purcahse. From here, you'll see all past purchases, along with any associated licensing keys.
Now if you made the purcahse through the new/current RPGMakerWeb.com site, then you may be able to access the key associated with your purchase. After going to
https://www.rpgmakerweb.com/, find the link that says 'LOGIN' on the top right portion of the page. Once prompted from the following page, enter your email and password. Once you've successfully logged into your account, you should be able to now access your past orders.
When you've found yourself successfully logged in, click on the link that says 'YOUR ACCOUNT', again on the top right of the page. You'll now be presented with a list of any orders made from the account that is currently signed in. The order number is the serial used to activate your software. It should look something similar to R123456789.
The reason support had stated that your key had been reset is because each software key has a limited amount of activations when activated on a new PC/new hardware. This is to prevent someone's serial becoming a participant in piracy. When they stated that it was reset, they meant that the number of uses allowed had been reset so that there would be no issue in this regard.
If none of this information has helped you, then you should again contact support explaining your predicament with as much information as possible so that they may be equipped to best assist you. Seeing as you have an 'Early Ace' forum badge, there's the possibility that the purchase was made from the old verson of the RPGMakerWeb.com store, in which case the best and/or only option is to receive your original key via support. Check your old emails too if you believe you might have a copy from your original purchase archived somewhere.