What to do about scams?

I was recently called with a message with one of those magazine company I believe it was publishers service and I dont know why but I agreed and gave them my credit card number I realized soon afterwords how stupid that was and tried to call them back and was hung up on after listening to some recording I looked at my account info and saw a pending status from them for 60 dollars I changed my credit card number immediately and need to wait before I can reverse the charge but what else should I do I have heard horror stories about these companies and that they send collections agencies after those that don't pay and harass you until you agree to pay them off to stop. Also I finally got through to a woman and asked her why I had been billed so soon she told me they bill it automatically to check if your card number works and that it will go away (I don't really know if this is possible if so why so much) I also found out that it was actually 60 bucks a month and not 4.95 as I had been led to believe what I had been told it sounded like 60 dollars total for 18 months anyways she told me could only put a hold on my account and a supervisor would call later but I got the call while I was at work and it was to busy to excuse myself to answer it so put it to voicemail but they didn't leave one. That all happened today what should else should I do and what else Will they probably do also I gave them a friends number I don't think he would be stupid enough to fall for it too but really I don't want them calling him to say that I owe them money or him or anyone else finding out about my lapse if judgement. So please if anyone knows to do next please help