Microphone privacy settings not working

I'm experiencing a very frustrating problem with my microphone privacy settings for an application I recently installed. I accidentally clicked on 'Don't allow access to microphone' when initially opening the app so went to the microphone privacy settings as I normally would in order to change this to allow access. I've run in to a problem though as the application appears in the microphone privacy settings with the check box already ticked but it won't check or uncheck despite clicking on the tick box. I've no idea what is causing this and i've tried reinstalling the app to see if this would fix the issue but it doesn't. The app was purchased at considerable expense for my business and it's disastrous that it's not working because of a seemingly simple issue!