Had this happen to me - when I rang them and they asked me for £90 I told them I wasn't going to pay it, and instead use the money towards a Wii.
2 days later they rang me back and offered half price repair and a free gift (read old launch game) for the inconvenience as it wasn't the first repair I'd had.
When I accepted, they asked what gift I'd like, so I asked what was on offer and they said I could have an accessory or a game
"Can I have the camera then please"
"Sorry out of stock"
"Wireless headset?"
"Sorry out of stock"
etc, etc...
Eventually I was offered a free game which came to...
"Call of Duty 2"
"I've got that already"
"PGR3?"
"Got that..."
"Perfect Dark Zero?"
"Got that..."
a few more games later...
"Viva Pinata?"
"Oh for god's sake - yes, just give me Viva Pinata..."
"Ok, but Viva Pinata's out of stock, can you wait 2 weeks?"
"What? Why can't I wait 2 weeks for

camera instead?"
Don't let them bully you into forking out, let them think they're losing a customer and start chasing you.