Sorry, they stole your money. This is a big advantage of theirs, they aren't regulated like a bank so they have no trouble taking money from marginalized people.
Do you not recall because you haven't read your own agreement, or because you haven't actually opened a merchant account with a bank before? You don't have to take my word. Type ["merchant account agreement" 180] into Google to see some 40,000 examples of bank contracts with that same hold period written into them.
And the OP case description is quite unclear, but the details sound like that it might be not "assets frozen while check if business is legit", but actually a threat of "charges filed against owner for circumventing anti-money laundering laws and assets confiscated".