合同规定的日期 meaning in English

contracted date
contractual date

If we withdraw the bid after the bid open in or before the expiration of the period of the bid validity , or if we , as the successful bidder , fail to enter into contact with the purchaser or furnish the performance bond within the period stipulated in the contract after the notification of award is made , the said bid bond shall be forfeited to the purchaser
如果在规定的开标日之后，在投标的有效期内撤回投标，得到中标通知后，没能在合同规定的日期内与招标者签订合同，提交履约保证金保函，则其投标保证金将被(招标者名称)没收。