Computer Repairs

My school, Palm Park Primary bought a computer on the 10th of February 2020 at LMWS INWESTMENTS.On the 06 if June 2020 I experienced problems with the computer. I took it in for repairs.On the 09 of April I took the computer in again, because the same problem occurred.They phoned and say the was fixed ,but as they talked the computer went blank again.They phoned and said the battery if the computer us giving problems.They asked if they can replace the battery .I said no problem, but Becerra did they mentioned that the school will be liable for the costs.When I fetched the computer on the 17th of May ,they said I need to pay an amount of R1099.The school refused to pay that amount because I did not even used it a lot due to Covid in 2020 and we had very little school days.Please help me fixed the problem.I asked them how can a computer give such problems within one year.?I have all the paper with and evidence with me.