call sb. back
回电给某人
He never calls me back
他从不给我回电。

get back to sb.
稍后再联络某人
You need to get back to me quickly on this.
你一会得快速联系我。

get through to sb
联络上某人
I always find it hard to get through to him.He never answers his phone.
我发现总是很难联系上他，他从不回电。