银行业务-信用证

UCP600三十五条

Article 35 Disclaimer on Transmission and Translation
第三十五条 关于信息传递和翻译的免责
A bank assumes no liability or responsibility for the consequences arising out of delay, loss in transit, mutilation or other errors arising in the transmission of any messages or delivery of letters or documents, when such messages, letters or documents are transmitted or sent according to the requirements stated in the credit, or when the bank may have taken the initiative in the choice of the delivery service in the absence of such instructions in the credit.
当报文、信件或单据按照信用证的要求传输或发送时，或当信用证未作指示，银行自行选择传送服务时，银行对报文传输或信件或单据的递送过程中发生的延误、中途遗失、残缺或其他错误产生的后果，概不负责。

所以我想你也只有自认倒霉，碰到这种银行，唯一的办法还是和客户协商改证。

应该是银行负责，你可以按照银行的保证书要求银行赔偿，不过这个风险你们自己也要承担一部分。