As of some days ago, If your account has been locked before 2016 due to inactivity, after you unlock it, your balance will be reduced to 0. You'll have to send them an actual screenshot of when you could see your balance to restore the funds to your account. There has been numerous reports both on reddit and on their own Telegram group chat.
What I'm trying to figure is if that is deliberate or an unknown/accidental bug in their system. Either way they haven't made any proper announcement.
Source: https://www.reddit.com/r/wex/comments/74iam6/wex_verified_now_account_empty/
This is what they will reply to you:
"Thank you for contacting the WEX Exchange Support Service. We do not have data on deposits and deductions from the previous site only on current balances. If you have any further questions, please feel free to contact us."
"We informed in the news that we don't possess historical data on transaction and orders of the old platform, that's why we cannot approve or deny your words about funds deposit. The funds were credited to the new platform WEX.nz in the amount shown in your profile. During the period after BTCE closing and before WEX opening, all transactions were fulfilled out of control of the old platform as well out of control of the new one."
This case only happens if you had an account prior to 2016 suspended, and now activated again (through the verification process).
They sounds like a bunch of scammers to me that gave you unnecessary hassle. Probably no bug in their system just pathetic ways to scam people.