After ordering and paying online for collection at store, after failing to get a confirmation email (despite me checking they had my correct email registered at time of order), Argos Twitter Helpers, after many messages and days of waiting, eventually gave me a collection number which was not accepted by the store. I had to cancel and buy again!, and be out of pocket by £199.99 for several more days waiting for the refund. They are refusing to give compensation for the inconvenience as well.
Basically, they end up trying to blame the customer for any mistake of theirs. I've had bad service from them before as well, but I will never again, because I will never use them again!