Can I get experience?

Sir I am a teacher by proffession ,last yr after my completion of studies and pg and 2 yr diploma in teacher training ,I had joined a private school affliated to cbse in Delhi as assistant Teacher from 1 April,there I signed contract of 1yr in July and it's time period was from 23 may 2019 to 31 March 2020 but on 29 Feb 2020 without any strong reason they had given me a one month prior notice that they will not continue me in next session that is from April 2020 and also when I asked for experience letter they denied and told me your report is negative and we will not give experience letter to contractual employee and they told me 4-5 experience letter is of no use as April and May was your observation period so you don't complete 1 yr and they had called me till March 31 2020.sir now I had also not been given my previous month salary as it is given in the mid of the month of coming month March ,sir please suggest me should I go and continue my job till contract but I need experience as it was my first joining as fresher in that school and I had done the job for experience and now they are denying for the experience letter also I had gone 11 months there butthey are denying me and also using harsh language and then I had not gone there,so what to do now please help and advice me should I have to go there and collect my salary or what should I have to do please advise.