GTEH has gone to the Expert Market where no one can buy shares until an MM pledges to support the stock through a 15c2-11 filing. That's as close to "disappearing" as a ticker can get, I suppose.
But they haven't gone bankrupt so far as a bankruptcy filing so far as I know. And "delisted" refers to companies on an actual exchange. OTC Markets just puts a ticker on a lower tier of their private platform.
I think your broker simply isn't very well informed about the OTC and uses terminology that isn't relevant.