petrol stations are ripping us all off!

[Garry Spice]

now i saw a fb post last week with a bloke whos put just one litre of fuel in his car and the price wasnt the same as the adverstied price,in fact it was one pence more...

now this morning i thought id give this a go at asda in sittingbourne...
the price per litre as shown on the big board was £123.7p but after careful pump control i had one litre of diesel only to be charged £1.24p...
shouldnt it be rounded down not up?
could i ask for my .7p change?
rant rant rant....