You are in Sweden and asking this on the UK boards, so I hope the rules are the same if not, you'll need to log out of this site, and log into www.ebay.com and ask the community there.
However, a seller cannot ask for more money than that originally on their listing. It's not fraud, but just an error on the seller's part to miscalculate the shipping costs, but this is their problem , not yours.
Send them a polite message under eBay rules, you do not need to pay any more money, you wish the item bought and paid for, to be posted not cancelled.
You cannot force the seller to send the item, but if they cancel the item contact Customer Services explain you did not authorise the cancellation they will place a defect on the seller's account.
@111offroad