I think they do remove the trace of the sale and the refund. I recently had a $2 sub sale (which sadly is unusual these days) and then got a notice that it was refunded, I paged back and the same image had a $1.20 credit sale, so I was at first thinking that the 1.20 sale got refunded for $2, but then realized they had removed the sale reporting. I'd much rather they put a red refund notice on top of it or something. At least it didn't make me go negative.