How to properly cancel Curves

Everybody knows what Curves is. It is the place where women can go work out with low-resistance training. They are popping up as frequently as a McDonalds. I tried it a year ago. When I was not active at all, it was a good way for me to get into some kind of training. After a few months of that, I went to Karate so I no longer needed to go. Here is what I didn't know. If you signed up for a yearly contract with them and it is coming out of your checking account, you have to submit in writing a cancellation of your yearly contract 30 days before it expires or they will keep billing you. I found this out yesterday. This is my $31 mistake. I think I missed my 30 days by a few days. Also, you may need to figure in that they invoice it on the 11th and it usually bills around the 15th. The lady told me I would be surprised how many people are mad because they get billed again. No SHIT Sherlock, I can imagine that people will get mad if you fail to mention this when you sign someone in a contract. So read the fine print and make sure and keep up with it.