termination notice

eilie_4

事情是这样的

在上个星期5我去p公司签offer letter,但是突然后悔不想去了
合约里写着

If you do not report to work on the above date stated in this offer of employment letter, you are required to compensate the organization amounting to one month of the basic salary as stated in this letter for breach of contract.
During probation, your service with the company may be terminated by either party with one month notice in writing or payment in lieu of notice.

距离我去报道的时间还有2个月，我已经问hr了，但是她要我赔钱才可以。
请问一定要赔么？
即使现在给她们resign letter也没用么？