If the seat is too low for you, you are plainly out of luck. You can adjust the seat height some, but the seller currently has it maxed out for its longest length. You can go lower, this would require cutting the top down, most bike shops should be able to do it, and its pretty simple.
There is a youtube channel "GCN" and they have a video to determine saddle height.
https://www.youtube.com/watch?v=FVu5Zrktm40
Measure yourself the way they did at 4:10 subtract that distance by 100 mm or 10 cm. That is hypothetically a starting point for saddle height, its the distance from the center bolt on the cranks to the top of the saddle.
If you were to look into this bike, make sure that the bike's distance from crank bolt to the seat is much higher than your measured height. Even if it is barely under your measurement, I would steer clear.