How to get out of a Pro Investor Course

In early November, I attended a property investment seminar. I already had debt issues with property which I was hoping to gain advice from this seminar. Against my better judgement, I decided to sign a form to start their Pro Investor Course through the Whoohoo group, @ $433 a month. Within 3 weeks of signing a form, a small investment property I have, got a HIA report slapped on it and no tenant, (I already had a large mortgage on my own property), and two other personal issues happened which would affect my funds available significantly. Within days of this, I realised I could not commit $433 a month to the course, and immediately sent a detailed letter to the Whoohoo group advising them of my financial woes and I asked them if I could defer the course and payments for 12 months. (They have already taken 1 payment of $433). Instead, their arrogant reply stated I could not defer the course and that I had to still pay all funds. They kept referring to their refund policy which, as I explained to them, only came into effect if you had completed the course. I have not even started it. They did offer in an e-mail to reduce the monthly payments somewhat, but I was upset by this time at their dismissive attitude to my request. The bank then cancelled my credit card and I told them but still they attempted about four times to deduct money from my account. They have just recently tried to pressure me further by sending out a request for payment from a Collection Agency. By now, as you can imagine, I have no further interest in doing their course because of their arrogance and continual pressure on me while I have other issues to deal with.
Just wondering if anyone else has experienced this before and if so, what did you do ? My other options at this moment are to see a Solicitor next week and possibly give them some free publicity on Current Affair ?