Hi Gareth,
It depends on what the issue is. It could be custom CSS you've added or something else. Both Collapsed Topics and Essential are GPLv3 and provided as is in the hope that they will be useful, but come with no support. I fix bugs in them for free but if it is site specific then that's chargeable support. Therefore if there is no Custom CSS then with your permission and a login I'll have a look, if its a bug I can see in either Collapsed Topics or Essential then I'll add it to the list of issues and will get around to fixing it at some point. If its an issue specific to your site then I'll say so but as I hope you can see that I won't tell you what it is without agreeing a fee for the service. Unfortunately I'm not in a position to provide un-financed site specific support.
Kind regards,
Gareth