Call centre madness

My friend sat opposite me in this Software Development Asylum is currently looking like he's going to spontaneously combust at any minute.  If I wasn't mildly concerned that the flying shards of bone might scar me should such an explosion occur, it would be almost amusing.  He's currently being batted between two call centres, both of which seemed to be based outside of the UK as he tries to get his ADSL line fixed.  Neither his ISP (Demon, in case you're interested) or BT seem to have anyone based locally, or with sufficient knowledge to actually get the bloody thing fixed for him, and after a week of having his calls mis-directed and being no closer to actually the problem with his internet fixed.

Ooh.. they just cut him off whilst promising to put him through to a supervisor - he now looks like he wants to kill everyone in this office as well as the Indian Call Centre.

I wonder if companies actually realise the amount of homicidal rage that stupid call centres and idiotic telephone menu's actually cause?  There's no doubt that my friend is going to cancel his subscription with his ISP - wouldn't you after being messed about for well over a week?  So just how much saving is there in having a foreign call centre compared with the amount of customers you'll end up losing?