Resignation from Bank

Due to the worst work environment of my psu bank branch and the mental stress causing with it I have stopped going bank for a period of almost 3 months to recover my mental health condition.The Bank has been issuing a show cause letter and I have not responded to it.I have received a third letter asking for explanation of unauthorised absence and to join the work immediately and threatening me they will take discliplinary action against me.But I don't want to join the work again as I cannot spoil my life.The clause in offer letter includes the following. "You shall not leave or discontinue your services in the Bank, even during Probationary period, without giving notice, in writing, to the Chairman of the Bank, through proper channel, mentioning your intention to leave or discontinue your services in the Bank. The period of such notice required is one month during probation and three months after confirmation or in lieu thereof, as compensation to the Bank, you are liable to pay a sum equal to your pay (being drawn at the time of such event) for the period of notice so required. Further, in the event of your leaving or discontinuing your services in the Bank, you are also liable to refund training expenses incurred by the Bank or the Sponsor Bank, for deputing you to such training." As per this can I resign from the job without serving 3 months notice and paying 3 months salary in lieu of?? So how should I proceed with so that my future job prospects are not affected.