海关查验，客人要求我们付柜子空箱费怎么回

各位大虾们 我们出了一批货，13个方左右，和客人上海商一起拼柜，结果被海关查验，客人听货代说可能近一两周内海关放行不了，就把我们的货落下，其他的先走了。 现在客人向我们取到上海到目地港总运费按体积平摊，其中13个方的运费 以下是客人回复， re: lost space charge i hope you will accept that you are responsible for the customs declaration in china. so you are responsible for providing the adequate information on the goods for the customs declaration. you had to declare matches to the customs, and you did not. problems he caused by your side and you are supposed to bare losses. we cannot absorb losses caused by inadequate declaration. we pay for the goods, and for freight to shanghai, for the freight to russia and customs clearance. we had planned the consolidated shipment to use the space of the container efficiently. and that well planned efficiency was spoiled by the inadequate declaration. as a consequence the container was shipped with one forth part of it empty. who should pay for the empty space? there only two sides involved in the contract. you created the problem – you pay. 求教各位，该怎么回好呀