@Lee Dowling - totally spot on!
I have no idea why it hasn't clicked with any of these companies that having someone on the end of the phone fully trained, bothered what people are phoning for, and having all the possible systems at their disposal for getting a result is much cheaper than filling call centres full of clueless, powerless morons, and pissing the customers off both waiting for them and dealing with the buffoonery once they get through.
I've had experiences much the same as yours with BT, Sky, O2, Orange (who unbelievably told me they "didn't have the time" to deal with an overcharge!), Talkmobile, Fujifilm (who's callcentre closed while I was holding) and loads more that I probably should be glad I forgot about.
To go on another slant, I have worked closely with callcentre "system admins" on a number of occasions (but never as one). The lack of thought into the design never ceases to amaze. It seems the simplicity of administration of such systems - or should I say the perceived simplicity - fosters the idea that anyone can write a callhandling script. They actually get really complicated really fast - particularly in a multiskill environment. Try telling a caller to one line what caller number they are when there could be a call to a higher priority line any second. That's probably the main reason why most callcentres don't do it. People get told they're called number 2, then suddenly they're caller number 5.
The main problems I keep coming across are (1 - mentioned several times above) what happens when a call centre closes while you're in the queue. The easy answer is that the lines close but the agents don't go home until all the calls are answered. Of course all the agents are on strict fixed hours and are treated like disposable shit, so go home immediately. and (2) Monitoring. Nobody usually has a clue what's going on in the callcentre, wallboards if they're present are usually based on the known, rather than the exception - e.g. some caller being punted off to some unmanned queue somewhere for 16 hours, and reporting tools are pretty much universally a work of fiction, even in the rare cases they are configured correctly. Tiger billing, Cisco webview for examples just punt out a load of stats that really do mean sod all. Management love them though...