I thought that is what you might have. i have had to repair many of these in my days as an AV Technician. I now see your problem, as all the sockets I have seen are closed body types, where you can't access the rings to free the stuck jack. Maybe its important to use TRS jacks with these, I don't know. I have used normal mono jacks in my mixing desk, which has the same type of sockets, without any problems, so maybe its just a badly made socket. You might be better to return the unit as it is, as this should not happen. I am presuming that your jack plug is of good quality? I have often wondered about whether the two ring TRS jacks can be used in a normal unbalanced socket, but that is a different issue. Good luck.