Okay, before I go to bed
In August(for example), I use my card in Tesco for a pint of milk. My bank takes the money out of my available funds to await Tesco's request for it and the payment shows up on my August statement. A week later, with Tesco not collecting the money my bank then reverses the transaction thereby making the funds available again. In October, Tesco realises and requests the money. My bank pays it out but, because this is for a transaction that happened weeks earlier, nothing shows up on my account as it was already on my August statement. Sometimes though Tesco(or suchlike) will forget to take the money at all, meaning I got my pint of milk for free. Again, I know how ridiculous it sounds that a company like Tesco or similar would forget to take payment, but it's something to do with the minimal amount of people that make payments for this sort of quantity on their card. A banker or someone that works in the finance department of a supermarket could probably explain it better than me, but that is how I understand it to be.
Hope this makes sense of a sort, goodnight.
(pooster found out how long a piece of string was on, Thu 10 Nov 2011, 23:50, Reply)