When in your example you work remotely for a client in London, this client demand you to work for a client or branch in Bangkok, you do not work for a client outside Thailand anymore, and because they ask you to be in Thailand it does not look remote work anymore.
Why should Vancouver be at fault? They always have the possibility to reject your application or give you a more appropriate visa without refunding any money.
A chargeback on your debit/credit card might result in getting your money back, but since this is fraud, I would not advise so.
Surely not in case you have the intention to travel to Thailand at any time in the future.
No refund, some embassies even mention on their website that in case they provide another visa as applied for the difference in fee will not be refunded.
It is your own responsibility to apply for the correct visa.