Send a few times. I covered the topic on the post I emailed a VC but never heard back.

多发几次，我写过这方面的博文，请看《我给VC发邮件，却从未收到回复》。

youdao

Matusheski said he returned the call and expressed his willingness to speak to a Pentagon official, but never heard back.

马图谢斯基表示，他回了电话表示他愿意和五角大楼官员谈话，但是却没有得到回音。

youdao

But he never heard back from her.

但是他再也没有听到她的回音。

youdao

She got his email address and sent him a message but never heard back from him again.

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But she said they never heard back from him.

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