I am new to selling (buy almost daily!) and my DM did the post office trip for me with my first lot of sales. I have just looked at the post office receipts and noticed that for a couple of items she was only charged £1.19 where the buyer has paid the (suggested by ebay) £2.80 that I charged. Would you refund the difference to the buyer at this point? I think I do remember a seller refunding me £1 or so once in a similar situation. If I should refund, how do i do it? Will I incur more PP fees for doing so?