读商务英语的高手，协助翻译，跪谢哦！

mlars翻译的很好，除了一个小语法问题。

We have sent another prototype to xxx company on Apr. 19. It's expected to arrive on Apr. 21. Please kindly send back the previous prototype we sent you. Sorry for any inconvenience caused.

We sent another prototype to xxx company on Apr. 19. It's expected to arrive on Apr. 21. Please send back the previous prototype we sent you. Sorry for any inconvenience caused.

We have post another sample machine to *** company on April 19th, which is expected to arrive on April 21st. Please return the previous one. We apologize for any inconvenience to you.

we sent a machine sample to the ...company on 19th Apr and it is expected to arrive on 21th Apr, but we are sorry to ask you to send it back , sorry for any inconvinence.