Hangs up call because we went over 5pm!

I am absolutely shocked by what I just experienced. I called to ask why I had been double debited for the month and because the call went over 5pm while we were talking, the call just cut off, and then said I must rate the call. We were in the middle of a conversation! How can they just do that? When I tried calling back it said please note our working hours are between 8-5. I didn't even get my query resolved