DiveTank is a great company and they have excellent customer service. Richard and his staff work hard to make sure everyone is taken care of.
However, they are located in British Columbia. Like many companies that do business in the US, they ship product to their Blaine, Washington wearhouse to keep shipping costs to a minimum.
Because they are based in Canada, they must charge your credit card in Canadian funds. If you purchase from them using your credit card, be prepared for exchange rate charges on your card. The exchange rate can fluxuate and every bank charges a different rate. The US dollar is weak against the Canadian Loonie right now, so it does not work to anyone's advantage. I travel across the border frequently, and I have seen differences as much as $.25 per dollar exchanged, depending on which bank you go to. That is a lot, especially if you are purchasing a drysuit.
It sounds Richard and his team are working with their US customers to make sure you have the price you were quoted. If this doesn't work, purchase through your LDS or a US based on-line dealer.