It is not! the fault of Hitbtc or any other exchange.
BTC network is clogged right now. There are 113000 unconfirmed transactions according to blocktivity right now. Some users are waiting for 3 weeks now to get their transaction confirmed, because they did not pay a high enough fee for the miners. The standard fee brings you directly to the bottom of the waiting list...
Miners always mine the most profitable transactions first. If they don't fix scalability you might wait for months now to ever get it confirmed...
Don't accuse Hitbtc of being responsible for it. Because they are not, the outdated sourcecode of BTC is.