The SEC crackdown on making a company provide adequate information on which an MM can make a market has no bearing on a brokerage firm not allowing a client to sell stock. They may not allow someone to open or add to a position a ticker that they consider below reporting standards like KKUR but they can't not allow you to sell it. You could ask them to remove a ticker from your account as a worthless security if it weren't trading but KKUR doesn't fit that category now that it's trading.
You'll have to call and talk to your broker to get the answer you need. Sorry.