Not for me. I would feel differently about booking with, say, the ICHG sites as they offer you a cheaper rate for booking in advance but won't offer you a refund if you have to cancel. Since they show no flexibility when the customer makes a mistake, then I see no reason for the customer to be gracious when such a company make a mistake themselves.

With Agoda, it is a bit different, they do allow a cancellation, as long as you pay $15 admin fee as a penalty.
Since they have treated me on the same terms (given me the equivalent of a generous 'admin fee' when required to cancel) I won't be pushing this any further.

IF the cancellation policy had been equivalent to losing the cost of one night's accommodation I would be looking at taking this further. As Agoda didn't impose a draconian and inflexible booking policy I won't either. They also informed me in good/reasonable time so that I had plenty of notice. I can make good use out of what is essentially a $35 hotel voucher ^