Reason Why.
Polo is not playing with the BCH. Literally costing them $1Ms per day in fees.
Also they froze the LTC wallets. Steemians always bitch about withdraws.
Loads of other wallets are 'in maintenance'.
The whitefish is a bit stinky!
Another reason is they might have deposited (your) BTC on Bittrex and Bitfinex to corner the market and make a killing.
I HAVE NO EVIDENCE ... but I have a strong opinion based on observation.
If they are losing so much money from not having BCH then they must be making an awful lot and not insolvent.
Most of their coins are in cold storage so unlikely to be missing.
If coins were moved it would be visible on the blockchains.
I withdrew about $25,000 of coins a few hours ago myself, so I don't see any problem apart from increasing pressure from the regulator, and continuing problems with enormous traffic on their site