Columbia House DVD Club www.columbiahouse.com Charging me for DVD's I didn't order. Refusing to cancel my membership. Internet

After receiving an email advertisement that advertised 3 dvd's for $1 each I decided to sign up for the Columbia House DVD club.  several months after ordering the 3 dvd's they started to charge me for DVD's that I did not order.  I sent them an email asking them why they did this.  They told me that they automatically send director's selection DVD's and charge for them.  I told them I do not like them charging me for things that I did not order and I told them that I wanted to cancel my membership.  They told me that I need to fulfill a commitment and order 3 more DVD's before I can cancel.  So then I ordered 3 more DVD's and told them again that I want to cancel.  Again they refused to cancel my membership.  This time their excuse was that I need to buy 3 more DVD's that each cost at least $19.95 or more and because the movies I purchased cost less than that they do not count.  The problem is most of there movies cost slightly less than the required $19.95 or more.  I wasn't able to find any movies I am interested in that meet that requirement.  So I am unable to cancel my membership and they are charging me for movies that I didn't order.