In my office, my colleague makes phone calls to clients. However, the client may not answer at that time. After some time, the client makes a call back to my office. Suppose I answer that call, and they simply say, "I got a missed call from this number?" How can I respond to that?
It depends on a number of factors, such as: Is your colleaugue there when the returned call comes in? If not, do you know when he'll be back in the office? Are you familiar enough with the nature of the call that you could handle the call? Do you have a caller ID system, so you already know who is on the other line? Depending on the answers to those questions, you could use:
"Yes, that was probably from my colleague David. Let me put you through to him."
"You probably did, but the person who called you isn't here now. Would you like me to leave a message?"
"You probably did, but the person who called you isn't here now. Is there a good time when he can reach you?"
"That was my colleague, but he isn't here right now. He was calling to ask if you would like to renew your subscription, which is going to expire soon."
"That was my colleague, but, unfortunately, you've missed him. I can let him know you called, though.
That was probably from David, but he's at lunch right now. You could try again sometime after 1:30.
This is Mrs. Jones, isn't it? Yes, my associate was trying to call you, but you've missed him. It looks like you two have started a game of phone tag."
Words I've bolded are somewhat idiomatic terms related to telephone conversations. My last response includes the term phone tag, which, according to Wikipedia, means:
A phenomenon in which two parties attempt to contact each other by telephone, but neither is able to get a hold of the other for a conversation. Both parties may leave a message on the answering machine or voicemail of the other, and request a call back.
It's a playful way to refer to two people who keep missing each other on the telephone. Mirriam-Webster mentions the term has been in use for a couple of decades, and its Learner's Dictionary says that this informal term is "chiefly US", so I'm not sure if it would be immediately recognized by a worldwide audience. However, I hear it used regularly in my workplace.
This is more a question of etiquette and business practices than of English -- I'm surprised there haven't been votes to close.
But to answer: It depends on a number of factors. Do you know who called the person? Do you know why he called them? What was the nature of the call? Are you able to conduct whatever business the original caller intended? Etc.
So for example, if he was calling potential customers trying to sell them something, and the customer calls back, and you can give the sales pitch, then I'd just do it. "Oh, thank you for calling back, Mr Jones. Yes, we were calling to give you an amazing opportunity to be one of the first to own the new J-Pad ..." or whatever.
If you know who called them but you don't have the information, skills, or whatever to take over the conversation, you can offer to take a message and/or have the person call them back.
If you have no idea who called them or why, then you are in an awkward position. What can you say? "I have no idea who called you or why. Maybe whoever it was will call you back." That's true, but makes your company look really inept. If this happens, your company has a problem with either its technology or its business practices. Perhaps you should get a phone system where each employee has a distinct phone number instead of an extension, so any return call goes to the desk of the person who made the call to begin with. Or perhaps your people shouldn't hang up when there's no answer, but should leave a message.
I used to work for a big company where when you called someone within the company, if their phone was busy at the time you called, you could key in your own extension number and then when the other person hung up, the system would automatically ring your phone and his and connect you. Except for the rather strange requirement that you had to key in your extension number instead of the system being able to figure it out. So every now and then someone would mis-key their number, and the system would call the intended recipient and some totally unrelated person, and then the two of you would have this awkward conversation on "Yes, why did you call me?" "Huh? You called me?" "No I didn't" etc.