Can I stop paying my Time Share?

We cannot afford our bills right now because we are paying about $500 a month to this time share. The money is automatically taken out of our credit card (with our bank), my main question is can I tell the credit card company to stop paying Silver Leaf?

Secondly is there any legal way for me to get out of this time share, I mean from just an ethical stand point (not legal unfortunately), we have paid close to $7,000 to them (although that only amounts to about $2,000 principal) and we have NEVER once used our week, we've not used any bonus time at all, we have basically just threw $7,000 into a hole and have never seen any return.

I understand that when you promise to pay somebody that you are obligated to do so, so we are legally bound to keep paying them right, but what do we do if we simply cannot pay? And is there any legal way for us to get out of this, I mean everyone knows that they flat out lie to you during their sell and then expect you to read the 30 page legal document explaining (obfuscatingly so) how they are not promising you anything they just did in the hour and a half sales pitch.