Hopefully you can make the existing school work. As others have mentioned though that if it is not fixable in any kind of reasonable time it may be best to remove your child and seek alternate arrangements. We did this with our DS4 as he was too young for kindergarten. Private school is expensive, the commute is a drag, but the program works, he has friends, and he is happy.
I really don't have many options here. The public school is the only other viable option, as we're zoned for a supposedly good one. However it is very overcrowded, so much so that the school just went year-round. They've already made the classes for next year, so if we switched now he'd be stuck wherever they could fit him, as opposed to wherever would be the best fit. I've emailed the vice principal who is the one who talks to parents and tried to make an appointment to discuss possibly transferring, but have gotten no response, which doesn't make me sanguine about how responsive they'd be to his needs.
There aren't any good private schools in my area. There are a couple of good ones that are a 40 minute drive away, but that really isn't doable for us. I'd have to spend almost 3 hours a day driving back and forth between home, school and work. He would have no time for any after school activities and would hardly ever be able to play with school friends since most would live far away.
There are only two secular private schools in my area. One is so rigid they suck all the joy out of learning and the other seems to be all show (fancy facilities, etc) but no real substance.
I love everything about his school except the academics. It is a small charter school with a very safe environment. While his 1st grade teacher was not good, his classmates were the nicest group of kids and families. If I pull him out, he would never get back in, which makes the decision really hard. The waitlist to get in is long. If not for this I would give the public school a try and if it didn't work out just go back to the charter.
