My insurance company mistakenly applied someone else's insurance premium to my account for my rental property and it appeared that a double payment was made so I got an erroneous refund check. Their premium happened to be the same amount of mine and it was a part of a bulk payment from my bank's escrow department that included my payment as well. The bank told me to give the money back to the insurance company and the insurance company told me to give the money back to bank. I started to shred the check, do nothing, and let the bank or insurance company figure out their mistake but I was concerned that someone's insurance would be canceled. Cashing the check was never an option. The bank was concerned and tried to help; however, the insurance company was the one that screwed up and they seemed annoyed that I called. It only took 13 phone calls and 47 minutes of my time to give back money that was sent to me by mistake.I received a check in the mail from my insurance agent in the amount of 22% of my annual premium for my vehicle, house, and rental property insurance with no explanation other than "over payment". It's a significant chunk of change. I am calling today to get clarification before I deposit the check. I like unexpected windfalls but in my experience they typically coincide with unexpected expenses.