Who called from 7186281649

Called and when I answered never said anything and waited a few minutes and they hung up.    I called the number back and they said they never called.

Called and when I answered never said anything and waited a few minutes and they hung up.    I called the number back and they said they never called.

Called me once and I hung up. They called back immediately but I recognized the number and didn't answer.

Called twice today. Told me that there was a serious problem with my computer. I hung up