Registration Code in Use?

This is happening to my significant other. She bought the game off bol.com and used the registration code it came with but it says the code is in use. She tried manually inputing it on mogstation after doing research on what is happening. And of course she contacting SE support. Till they respond she has been trying to fix the issue on her own. She double and triple checked her account on the website for any alerts, notifications, private messages and her hotmail. She even tried using her code on the early access/pre-order screen or something like that and it worked, giving her a new code...that also said invalid.
Anyone have any advice other than what was listed about why this is happening? She has not bothered to activate service yet so that her 30 day free trial is not going to waste. I did not have to activate mine first before activating the game so I told her not to activate hers so that her trial is not going to waste lol

Edit: She has checked multiple times over the period of 2 to 3 days for any codes in her email or on the site, is what I mean

Are you sure it was a brand new copy?

She said it had plastic wrap on the game case and everything so she's positive it was new.
While she was typing the code for the first time she said her net happened to drop her she thinks that might have caused the problem but I personally doubt it lol just seems like it wouldn't stop the games product code from being registered but not like I know 8D

Sorry, I have no ideas how this can be fixed unfortunately. Hopefully support will get in touch soon.

No worries!
We both hope it will be sorted out soon too :3
If worst comes to worse she tries and get a refund and I just buy the game for her from wal-mart like I did for me but we hope we can get this sorted out too!
Just wondering if we can get help here too is all, since customer support can take a while to reply~