I usually don't post things like this.
Last week my fast charge usb cable for my phone started to play up.
I went to twitter asking Samsung UK if they sell just the usb cable. As ones of Amazon aren't to be trusted, and I'm unsure what other sites sell genuine ones.
Anyways, Samsung got back to me, but they were asking for information on when I purchased my phone, warranty information and proof of purchase. As it's on contract I couldn't get pricing or vat information so samsung wouldn't accept it.
I went to Vodafone via Twitter and explained the situation. Where they tried giving me proof if purchase. I told them it needs vat information or its no good.
a day later I got a phone call about the situation. The lady on the phone said, because I couldn't go through samsung, Vodafone were willing to adjust upto £20 off my next bill if I went out to purchase a new charger and show them the receipt.
Checked online for cheapest genuine charger, was at carphone warehouse for £20.
On the way to the store, I popped into o2 to see if they had stock. They priced the charger at 25. Member of staff caught me before leaving the store, he asked me if I needed help. I explained I needed a charger but it's cheaper else where. When he said he'd give me a discount bringing the charger down to £18.74. (cable and usb plug)
As I mentioned about the Vodafone thing, he printed my name and number on the receipt as further proof of purchase. He even mentioned he used to work for Vodafone and he knows they do this sort of thing.
I sent that off to Vodafone and within a day I got a phone call confirming they'd credit my account that £20.
I'm still fairly shocked they'd even offer to buy me a new charger/cable.
Might be something to consider attempting.