Going to get fired because i wont be bullied to work the last hour of my shift due to daycare closing early

♡ 𝓚𝓪𝓽𝓻𝓲𝓷𝓪 𝓵𝓸𝓾𝓲𝓼𝓮 ♡

I work part time in customer services and i have worked for this company for 2 years. I am a single mum and my son is 7, i get no suppprt when it comes to people watching him so i am his sole carer / provider. Very recently the afterschool club changes and is now held at the school meaning they open until 5:30, however i noticed on the day before half term it was only open until 4:30 which school confirmed and unfortunately i am on late shift which is 1pm till 5pm and i told my manager straight away. She told me she is going to discuss this with the director because no one can cover between 4 till 5pm. She told me they cant change the shift, i explained that theres no option but to get my son from school or he will be left outside alone and social services will be involved.. they dismissed this and kept repeating themselves. They tried to get me to book it off as a holiday but i cant as i have none left and i got told im not being fair on the other people...... they are now going to be having a meeting with HR and higher management as they cant "substain " this any more implying this happens alot which is doesnt. She also said that they will be discussing that im about to have unauthorised absense , i told my manager that the important factor is i have no choice but to collect my son due to a childcare issue. My colleagues told me they didnt get asked to cover my shift and one said she would cover it, but i think we are beyond that now as the company are clearing trying to get rid of me. I told HR what is happening and they immediately took the managers side as they always do because they are corrupt. I never have to have people cover my shift due to sickness or something school related. I told my manager 3 weeks in.advance and she did nothing. Also, she changed the rota meaning i am alone for the last hour on ny late shifts for the next 3 months. I spoke to legal and they have advised it sounds like im being targeted and singled out and its discrimination. What can i do?