I understand that and 120 works out to roughly the amount I've been paying (I have been paying with Facebook credits for a while.) I think I went wrong somehow this time as there was an offer for 525 credits for £31.76p and that is what my receipt is for. 250 went straight onto Farm Town which I thought left 275 credits but apparently it doesn't - it leaves 176.

That's what I don't understand because when I went to school - admittedly a long time ago - 250 off 525 leaves 275 so I presumed that's how many credits I would have left. It's obviously me getting confused so I'm sorry as I'm probably being very annoying.