This problem demonstrates probably the biggest success and the potential failure of Internet companies.
On the one hand, Play offer massive choice, great value and a 'free' P&P system. They also tend, in the majority of cases, to offer a next day delivery system assuming the product is in stock and you order early enough in the day.
On the other, people are now totally expectant of next day delivery, very low prices and a large choice of films.
Basically the bar becomes heightened to such a level that the companies simply cannot consistently deliver against their customers expectations 100% of the time.
I did it myself the other day, ordered an in-stock DVD from Play at about 3.30pm. It didn't come the following day and I was annoyed. Thing is, even in a close geographical area, you have to get a first class letter/package in the post before 4pm for the PO to 'guarantee' next day delivery... so I was expecting Play to get my order, process it, pack it and have it posted from Jersey by 4pm to get to me next day. Looking back, it was unfair on them to have that expectation BUT the damage against their reputation in my mind was already done.
Remember, another benefit to Play is that you can see exactly how your order is progressing. If they posted it three days ago, it's hardly their fault it hasn't reached you yet. If they haven't posted an in stock item 4 days after receiving your order, then they owe you an apology... the thing is, at least you can check this.
Yes, they should definitely answer customer emails with 24hours (within 12 would be better, assuming you don't email them at 9pm).
Yes, they shouldn't ever make mistakes but it's humans picking and packing those DVDs and I dare say they're not the highest paid or trained individuals.
I still think it's bloody amazing that we can order such a huge range of films (especially R1s) at such low prices and often get the goods next day or sometimes even before the official release dates.
I also think there are probably a good 500+ people as members of these forums who buy regularly (once, twice a month) from Play and look how many have actually posted negative comments, maybe 10 or so? Again, most companies would relish a 2% customer dissatisfaction level.
Let's keep things in perspective. The last good thing... if Play really DO go downhill for good, there's always others snapping at their heals for the business. God bless the Internet
BTW, I have no connection to Play and am sure they mess up like every other company does on occasion. Bonesy is right though, once a company has messed up, it's the salvage work they do to put things right that is the measure of them... so keeping fed up customers a little happier would be a key area for Play to improve.