I tried calling you on your mobile.

我试着打过你的手机。

A：I tried calling you on your mobile.

A：我试着打过你的手机。

B：What time was that?

B：什么时候?

A：It was about an hour ago. But I couldn’t get you.

A：大约1小时以前。但是不能和你联系上。

B：I was on the subway. I don’t think you can get a signal underground.

B：我在地铁上。我想地铁里没有信号。

There are various situations and reasons for not receiving a phone call.

有很多情形和原因不能接到电话。