Trident Hotels - Invalid charges taken

This is with regards to explain and bring to your notice that how were we wrongly informed by the hotel people and thereby incorrect charges were billed to the credit card. We got the booking confirmed on *th November (details attached) for ** nights (**th Nov **** to **th Nov ****) for one my friend. However, due to some unforeseen circumstances, the guest did not show up.
On **th Nov ****, we informed the hotel (Sales manager) to cancel the booking upon which the hotel (Sales manager) informed us verbally that, as per their "policy" they will have to charge for * nights. We "assumed" they are telling us the truth, so didn't check the cancellation policy and agreed for a charge of * nights as a "cancellation charge".
Later, when we checked the cancellation policy (under booking confirmation document and global website) we understood that we were charged wrongly and we should have been charged only for * night and not * nights. As per the cancellation policy (in the invoice) confirmed booking when cancelled within ** hours of the date of arrival would be liable to pay for one night only. We cancelled the booking within the stipulated time but were wrongly informed about the cancellation policy. On the other hand we were not informed at the time of booking of any such rules nor we find mention of any condition/ exception under the cancellation policy, that when the booking is cancelled after the "arrival date" or a "No show" situation or a "special booking/ cancellation rates" or any "Retention Policy" as such that, it would attract any additional penalty in addition to the official "cancellation charges", which makes me eligible to pay only for one night upon cancellation whatsoever. The credit card company had put a block on the card for two months as a dispute had been raised. But the hotel had charged stating that I had given email confirmation to deduct the charges. This whole transaction has been an annoying and stressful experience and I look forward to some positive feedback from your side. I have tried to speak to senior management, but there is no response from their side.