Interval International / IntervalWorld.com review: Fraudulent charges

I booked a cruise exchange and an additional cabin with Interval on Dec 31, 2011. At the same time, I booked a shore excursion for 4 people (2 per cabin). The shore excursions were $55 per person. I rec'd an email only listing 2 people. I started calling in January to try to confirm the booking for 4 people. I have been shuffled around and repeated emails and calls have not been answered. I rec'd an email from Interval yesterday stating I needed to call Port Promotions directly. I did and they did not have any booking for me at all. I paid them $220 to schedule the 4 excursion that Interval already charged me for. I spoke to Interval today and they said I was overcharged on my deposit by $110 but it wasn't the shore excursion, just a mistake. I have the breakdown that Interval sent me in January and it clearly lists the shore excursion charges for both cabins, $110 per cabin. She said I was wrong and that was internal invoicing and Interval doesn't owe me anything and told me not to contact my credit card company because I was confusing the issue. I want my money back and the interest for the these charges for the past 5 months. Interval promotes the excursions on their website and their booking agent suggested the excursions. I was charged 5 months ago and they have double talked every time I call them. I am very upset that a company does business this way. How many people have they charged for shore excurstions that they never booked? It's obviously a scan and I will never use Interval again and I say BEWARE to anyone who attempts to use Interval for their travel accomodations!