Roundcube is only 12% full and is not receiving emails

I've been having issues with Homestead email so long that I'm having customers use a gmail account I had to set up months ago, but it shouldn't have to be this way, I pay for email that is not working. Currently, my Roundcube is only 12% full and it will not receive emails. Any clue why? I need to get this fixed, how does Homestead expect people to run businesses when something as basic & essential as email doesn't work for months at a time?!