I have found the same problems and I think you will find upgrading to Frostwire 5.3.3 will cure at least the overheating problem.
As for the refusing problem is concerned. I have not yet encountered this with 5.3.3 but I did with many versions including 5.3.2
To close Frostwire when it sticks on Shutting Down, click on > Force Quit > Select Frostwire from the resulting list and click Force quit.
Please do not Private Message me with questions that can equally well be posted in the forums, and may also help others. Do use the forum search.