you can trade just can't withdraw/deposit yet. block are taking long should start speeding up a bit now the difficulty has adjusted. they have to wait to make sure miners mine it. viabtc is letting you deposit but I have been waiting forever for confirmations. Good thing is they let you trade with just 1 confirmation but you can't withdraw till you get 20.
But reality is a bit different, then it's written on their website.
They writing it should be deposited after one block,
but no, no. Already sent 12 blocks before, still zero confirmation on their site,
so be careful with them.