You said you deposited about 26.5BTC.
Where were those funds originally sent from? Maybe post a trans ID
I think the reason why they haven't replied is because many those BTC come from a trainted trail or some stolen BTC.
Either way they have to respond to the user and state clearly what is the delay rather than playing the judge. It will be a good thing to post his transaction ID which will give more clarity to the situation.
There was a similiar situation with the $30 million tether hack last year. Somebody bought $10 million tether off the market which ended up being locked up.
I am not sure how you are able to purchase millions of coins off the market, either way it was a foolish decision and an unfortunate one.
If your BTC came from illegal sources, you will have issues getting it back.
If the team have the evidence, they have to produce the evidence rather than holding the coins.