I can explain that one. People will spoof numbers and then call from that spoofed number. It happened to me this year. Luckily, a friend of mine also had his business number spoofed earlier in the year and explained it all to me as AT&T had explained it to him.
In our area, they were spoofing the number and dialing the same area code and exchange code. For instance, if your number is 513.341.2897, they would dial all 513.341.XXXX numbers. The thought is you are more likely to answer that number because you automatically assume it is someone decently local and may have a legit reason for calling.
So I was receiving all these call backs from people saying they had missed my call. Even though I knew what was coming after the first call, I answered each one of them because my number is published for my business and I need to take each call. I briefly explained what was happening to us with the calls and said they may soon have their number spoofed so they need to know. I also told them that they could look my number up and see that it is my business number to verify who I was and that if they ever receive a call from my number, they would know it is a scam and should not answer it. We also talked about how they could verify this with their phone provider.
I went through all of the trouble of explaining this to each call I got because 1) it was my business phone and I did not want people to circulate bad information about my business, and 2) my wife received a call back when her number was spoofed and she merely denied that she had called. The person called her a liar and was extremely rude because he knew he did indeed miss a call from that number. I figured it was better to handle the calls in an explanatory way.