UNDUE ENRICHMENT

I enrolled at Irene swim school in January of this year, upon enrolling I was told to pay a deposit of the months fee in addition, that my notice month the said deposit will be utilized. in October of this year I accepted a job offer in Kwa Zulu Natal in which I sent through a one months notice via email attaching proof of my departure from the province . The owner rep**** saying according to her contract she does not allow November as a notice period . I did inform her again that I am leaving the province first week of december , I cannot pay for december when it is clearly beyond my means to attend such lessons . Her attitude was she will hand me over to her attorneys . My issue is the following can a contract stipulate when you cannot give them notice? and secondly why should I pay for swim lessons that I cannot attend , yet I had given the swim school in terms of the law one month notice and my deposit will be utilised , The owner only seems to threaten me saying she will hand me over. The very nature of the swim lessons is that the person has to present which I cannot be.