Yeah, beware of these cheap bikes with wheels smaller than 20". I had a bad experience with one too.
For food delivery, I think you will find it won't go enough miles on a charge and that the seat doesn't go high enough for you to get good torque pedaling it.
I think you need to spend a lot more if you want to do food delivery on an eBike in place of a car. Something like the Lectric Expedition with the delivery package. You'll need to raise your budget, though.