Hi @neuritiscanada - I'm sorry to hear about this experience. While we aren't able to force a seller to complete a transaction they aren't interested in fulfilling, there are consequences for their behavior.
A seller cancelling an order is subject to a defect on their account - which can impact their standing with us.
Additionally, as a buyer who has paid, you are able to leave feedback regarding the transaction that you feel matches your experience.
As you know, the vast majority of the sellers on eBay work hard to give you a great price and speedy fulfillment. I hope this experience doesn't sour you on using our platform in the future!
Tyler,