Over charged on postage

[milly33-uk]

BOUGHT AN ITEM AND PAID £3.50 postage but postage receipt on parcel is for £2.80. I questioned this with seller and confirmed postage was only £2.80 I'm fully aware this is only a 70p difference and because the seller was difficult when I questioned this just wondered where I would stand on getting this back? Don't want to seem petty but I have paid postage before and if its cost more seller has contacted means I've paid the difference but shouldn't it be the same if the postage is less?

[thisisabrandname]

There are 2 P's in P&P

one P is the price of the stamp,

the other P is the costs involved  in getting your item to you safely,

this includes the cost of the packaging,

ebays 10% fee on the amount paid,

plus other costs the seller may have incurred

you agreed to the P&P when you bid,

you are not entitled to any of it back.