Keep receiving mysterious phone calls

Keep receiving mysterious phone calls. What is going on.

People keep ringing me. I don't answer but get a missed call. I then ring them back, and ask them what they were calling about.

They then say they never rang me and it is "weird" and "strange", and I must have the wrong number....even though I received a missed call from them to begin with.

Once or twice, I would pass this by. However, this is happening a lot and it's getting very weird.

Why would people call me only to say they never did when I ring them back. Their phone wouldn't be ringing me by itself would it?

What's going on here? Matrix glitch? I want a rational answer.