They have kept trading open so you can exchange dogecoin without any problem. But the most surprising thing here is that the rate on hitbtc is several times lower than the market price of dogecoin. This is a totally trap set by the hitbtc team for their customers, and the OP has fallen into that trap and now has no choice but to incur huge losses.
This issue of Hitbtc to withdrawal of $DOGE start since last year and I'm surprised that they still didn't fixed the problem. One thing I doubt about this accusation is how the heck OP will deposit huge amount of Dogecoin to Hitbtc without checking the price of the order book. There's a lot of top tier exchange like Binance and Kucoin that accepts $DOGE with the updated price yet he still deposit on Hitbtc with lower rate.
Coincidence? OFC Not.
OP bought cheap $DOGE to hitbtc and he is using this scam accusation to push Hitbtc to release his $DOGE(as if hitbtc will read here) that he bought cheap. He is just trying to make a quick profit by selling it on other exchange.
Check reference on how long does Hitbtc have problem on DOGE withdrawal:
https://www.reddit.com/r/hitbtc/comments/q7fh0d/doge_withdrawal/This is interesting turn of event, I have to admit that such possibility didn't cross my mind, and judging from OP's effort to find the end of this situation --which I'll say pretty minimum because after they posted the opening post, they're not commenting or gives any other follow ups like they're not too interested or absorbed into this matter, although their fund is the one at risk here-- it is quite a possible scenario.
So,
dfbtc, just to clear the air here and be sure of your position, can you please show us the TX details from your address to hitbtc?