I need to issue a complaint.

我要投诉。

Ok,you need to go to QA department.

可以，你需要去质保部。

Where is the manager? I need to issue a complaint.

你们经理在哪?我要投诉。

I'm sorry.Our manager is on business.Maybe you can tell me what's going on here?

实在抱歉。我们经理出差了。或者你可以跟我讲。

重点讲解

I have something to complain.

I need to issue a complaint.

Issue是“发行，发布”，complain是“抱怨，控诉”,在上述表达中issue a complaint是指“投诉”。 I have something to complain.仅限于口头表达自己的不满，但I need to issue a complaint.指要告诉相关权威部门。寻求解决，这种说法更为地道和标准。