Agreed on a refund of R800 which is not paid to da

good day I would like to know if this can be done via this channel I have rented a single room. the rent was R1800 which I paid deposit before moving into the single room. I was asked by the landlady to pay a small amount to secure the place which I did and the balance was paid on the 28 February 2015. There was no contract between myself and the landlady and monthly an amount of R1800 was paid excluding lights which was prepaid which I provided. on the 31 July 2015 I moved out as there was no outstanding amount I was not given notice I gave short notice. The landlady was there while I was in the process of moving and what ever was found wrong in both our present I acknowledge and took full responsibility and the landlady explain to me that due to short notice and the errors that was found she will only refund me R800 which we both agreed. when I call to find out about my money she stated that she had to replace the dry wall which and the curtain rail is broken which I knew it was not broken it was firmly mounted in the wall so I removed it and place on the window pale I have sms's and once her once and she refuses to give the amount that was agreed please help me