There is a big flux of folks reaching the end of their tether when it comes to bullying right now.
I've been there.
It's heartbreaking. It makes you feel helpless and angry and frustrated because they seem to care far more about protecting their reputation and the bullies rather than the victims. The school and the LA can make you feel crazy, as though there is something wrong with you or your child. They can be bullies in their own right.
My heart goes out to you and I will say do not wait another day.
Not one more moment.
The first thing you need to do (in England and Wales, it's more complicated other places) is send a formal letter of de-registration to the school. A sample you can find HERE
After you de-register (and do make sure you get a dated receipt) my advice would be to join some local Home Education facebook groups. You might hear from the LA (Local education Authority) quickly or you might not hear a peep. Your local groups will be able to tell you far better than I can what to expect from the LA. After de-registration the school can not call, email, send letters, threaten or harass you but on occasion schools do. You do not have to answer them. You have not and are not breaking the law.
You never have to have the LA come visit you if you don't want to, and if someone doorsteps you (ie just turns up one day) you can politely tell them to make an appointment in writing to discuss things with you. In fact you can keep everything in writing should you desire, which is often a good idea. Some LA's are amazing but some are terrible and are not above bullying or lying. Do bear in mind that the LA only get funding from the government for each child AT school and they may have targets or external pressure to push for your child to be in school.
If your child has been bullied, it's going to take a while to heal, for your child, for you and as a family. You are going to need some time together to talk about things that might be difficult to hear, but you are going to need to hear it to know where your child is at. You can set aside time, one on one, to do this. Maybe once a week for an afternoon, or a little bit every day. It's not an easy thing but you have already done the hardest part.
The next bit is to de-school which I have written about HERE
While your child is focused on having some fun and healing this is a good time to research what kind of HE you will want to do together. Do want a bit of Classical Trivium or a Charlotte Mason curriculum? More on that HERE
The next part is a bit weird. You have to imagine what you want this journey together to look like (it might not ever look as you imagine). I would recommend learning something together (not you teaching) even if you suck at it. It helps to heal and repair trust in adults which have failed them at school so badly. It's also a lot of fun.You have to figure out what your goals are together and as individuals. At the end of the day a happy healthy and whole child with no qualifications at 16 is far better than someone who was miserable, hurting and hating with papers out the wazoo.
Home education brought us as a family a joy, a peace and healing I never ever imagined. My daughter may never sing the way she did before school (much to my heartbreak) but she not fearful, bruised or afraid any more.
Home education is far too important to take seriously.