Here's a little quandary I'm in, please give your input:

Two years ago and again last spring I received my shots for my trip to Kenya. In all, it was over $500 and I was told that insurance would not cover this. All right. Then last summer some friends of mine were going to Ethiopia to adopt a child and told me that their shots were covered, so I contacted my insurance and they told me that I should not have been billed for these immunizations, which led to hours of phone calls between the insurance and health care provider. In the end I was reimbursed for what I thought was the full amount but didn't check it exactly. The checks came from the insurance.

Then, last week, another check came from the health care provider for what as the exact amoung of my bill two years ago. Now, I felt that I had been reimbursed, so I am convicted that this money is not mine and should not be put into my bank account. Should I call and let the health care provider know that and return the check? What if I donate it to a charity? Would that be wrong? I think my conscience would be clear with that. But what is the health care provider then finds out it made a mistake and wants the money back, then I'm out $362. What advice can you all give me? What would the Bible say about this situation?