The most ridiculous thing

Yesterday I received a check for $366, a refund from the gas company. So today, not understanding the reasoning for this, I called. According to the customer service person, I made an extra payment of $366 on the gas account for my old apartment recently, so they are sending me back the money.

Really? Isn't this something I'd remember doing?

My regular gas bill is about $25, every other month. I had an invoice for an 11 cent adjustment recently for the old apartment (I believe because the new tenant moved in and they did a physical meter read) but there is no way I overpaid that by $366, as the customer service rep suggested. But I also can't imagine that a new tenant would be stupid enough to make a payment of $366 to them upon first moving in.

He told me that maybe I should think of it as an early Christmas present.

Yes. Basically, he told me that it's mine to keep.

I don't think that's true - if even a year from now, they wake up and notice that the $366 payment was erroneously credited to my account, they are going to come after me for it.

Yet I can't help but feel this is karma payback for all of the stress the other utilities companies put me through when I moved in.