It may well be fraud ...
The site is not allowing to withdraw as "access denied"
This happens when you don't leave enough in your account to cover the transfer fee.
For example if you have 1300 UCASH
Transfer 1000 and leave 300 in your account to cover transfer fees. If you try to transfer without leaving 300 behind to cover fees you will get an error message.
Also make sure you are in the right section. You have to log in to the main site and click menu. From the menu select send ucash.
I did a transfer off 299 to BTC Alpha trade. Just to check if it really was 300 transfer fee.
It's not it's 5 for transferfee.
That said I did the withdrawal almost 2 hours ago. Still have not received it in my Alpha Ucash wallet.