I have had this problem once before. I am not sure how, but I ended up with 31.3 hours of conversation. I tried to type in -30 to cancel it, but nothing happened.
Also: When I read my imported lessons, the number of the words that I read does not automatically show on my page. Why?
It looks like you’ve had a few conversations in the past week amounting to a couple of hours. Try subtracting 25 hours and see if that works for you. 
Are you clicking the LingQ’d button after finishing these lessons? Remember that the words of reading only updates automatically when clicking the LingQ’d button, otherwise you will have to increase the number of times read.
Thank you, Alex. I guess I will never learn…
Things could be a lot worse