While I find the tutors 99% great I have had problems with two. Customer service did rectify the first issue by crediting me an hour for my problem. Today I had a second issue which they did not resolve. They began by saying they would credit an additional hour but then expressed that I was over credited for the first issue and I would not receive a credit. The root issue was lack of knowledge from the tutor and a second tutor entering the session. To be clear, you will lose the time from the first tutor so if you are in a session decide if it pays to wait to see if you can redeem the session with the second tutor or you want to cut bait and end the session and start a new one hoping you can complete you problem within the session time.
To be fair until today I have had a very good experience with Tutor Vista and hope this is the exception not the norm...