My preferred way to get leverage when removing pedals is to orient the pedal at about the 3 to 4 o'clock position on the right side (drive side) and 8-9 o'clock on the left side pedal. I then put my foot on the pedal then put my weight on the pedal to push it down while pulling up on the wrench. It can be a bit tricky keeping your balance doing all of this. If needed, get a helper to keep the bike upright ans apply brakes, so you can concentrate on keeping your own balance and perhaps even use both hands to pull up on the wrench.

I also strongly suspect the OP is turning in the wrong direction. Apparently it is a new bike and they recently put the pedals on it. Seems very unlikely the pedals have gotten stuck in such a short time.