Kim Brothers Tae Kwon Do

I bought a groupon for 10 classes of Krav Maga defense.
I did not see a schedule on the website, so I contacted the Kim Brothers via e-​mail to ask what their schedule was for classes.
I got a response that they hold Monday & Wednesday «7:15−8:15 classes and Saturday 10am».
I replied back saying I would like to attend Monday and Wednesday and asked if I needed to do anything before coming in. I never got a response.
Assuming that 7:15 meant AM (morning), I drove all the way to the place and saw that they had an «OPEN» sign but no lights were on. I thought it was odd, but I figured that if the OPEN sign was on, they must not be fully open yet.
I waited a couple minutes and it looked like no one was coming.
Met with disappointment, I drove back home and sent an e-​mail to the Kim Brothers asking why they weren’t open when they said they were.
They responded with 3 e-​mails asking what was confusing at first, but then realized they had not read my full e-​mail thoroughly and acknowledged that they meant to say 7:15 PM not AM.
It seems laughable, but when you wake up at the crack of dawn excited begin a class that teaches you to protect yourself in the case of a dangerous situation, I had hoped that there was a more clear way to get basic instructions on how to attend a class.
If the Kim Brothers are not clear on explaining a class schedule, then how could I trust them to teach me the basics of protection?
Disappointed.