Unfortunately it sounds like it might be a terminal fault. If it's within the first two years of owning it then it will be covered by warranty. If it's outside that you either need to pay for a repair or replacement.
There are quite a few First Gen models on the second hand scene now, which may be cheaper than what Sky quote. Most buyers will expect you to collect though due to size and weight. Try eBay, Gumtree and Facebook Marketplace maybe.
