I ordered goods to the tune of £75 about Wednesday from M&S - I was to pick them up tomorrow (Sat) - anyway they send me an email to say they were in store so now I have got them but money hasn't come out of the online account. I said to lady in M&S - she said "oh yes but the money has been taken" but I say "oh no it hasn't". Has a mistake been made here.
The difference between your balance and your available credit will be the amount you have spent on-line or in shops, which may take a couple of days to appear. In my experience the only thing debited instantly are cash withdrawals.