RBC Visa overcharged refuses to dispute
I'm looking for some expert advice on a nightmare transaction I had made in haste about a month ago. I bough a DSLR online from www.dailydealdigital.com because they advertised it for a fairly nice price (not anything crazy so had I known what I know now I would have gone with the 10 others on Nextag that had it for the same price). I ordered the camera, the total for which was about $3200 and assumed that that is what I'll be charged since shipping was advertised as free. Two days later and no invoice/receipt from Daily Deal Digital my RBC Visa card gets charged around $3700. I called them up to complain and the same guy that answers all the phone lines there told me that the total was more because of shipping and tax, yelling I requested an itemized bill which he immediately emailed while we were on the phone. Apparently they charged me $200 for shipping and $214 for tax the funny thing is that the sub total + S&H + tax didn't even add up. I freaked out on the guy and was told that everything will be sorted out. The next morning I got an email saying that my total has been adjusted and the credit was issued. I waited a week for the credit + my camera and received neither. Called RBC VISA, who said that in order for me to challenge the charge I have to wait a month to not receive the goods. Literally 29 days later I got the camera but still no credit for the tax, S&H and bad math. The merchant is not replying to my emails and puts me on hourly holds or even hangs up on me so I called VISA again to see if I can challenge the charge and they told me that so long as the merchant sent me a bill saying that they were going to charge me these amounts, Visa cannot do anything for me.
I am now completely lost, how is it possible that these guys completely went to town on me and VISA cannot do anything about it. Do I have any options or maneuvers? Has anyone been in a similar situation before and walked away victorious?
Sorry about the super long post, but it's been a super long saga.
Thanks in advance for your input.