Hi,
Bitcoin is trading at 9000 USD right now on WEX.NZ, while on other exchange plateform it turn around 7400/7500 USD.
Do they have problem or anything ?
When an exchange has issues with their deposits and/or withdrawals, then it pretty much always results in their internal market prices not aligning with the rest of the market. This is exactly what happened with WEX.
There were both fiat and crypto withdrawals being halted in the system, causing the prices of certain coins to artificially inflate.
Two of the coins that are supposedly still open for withdrawal are ZCash, and USDT. Both of which are trading at over 300% premiums, which is not surprising. People are essentially paying extra to try getting their funds out instead of waiting for a fiat withdrawal to finally come, which is significantly more risky.
Even though there may seem like an arbitrage opportunity here, there really isn't, as the withdrawal system is completely screwed right now. I'd suggest not using them, especially with their track record of being shady.