I have.
Against LAFitness a few years ago. I had a gym membership with them but then I moved to South America so cancelled it before leaving as I wasn't going to be within thousands of miles of an LAFitness.

I cancelled over the phone, as well as wrote a letter to confirm I wanted my membership cancelled.

I get one more statement before leaving for South America and it shows no LA Fitness charge so I figure all is well.

While in South America I only got mail once every few months. Would go in to the city to pick it up from a place that would hold on to all my mail for me, including credit card statements and what not. I was never using my card down there so figured I didn't need to check statements often as I had no recurring payments - or so I thought.

I check my mail and see that LA Fitness has started charging me again at an even higher rate than what my old membership was. Now I'm trampsing through the jungles and mountains of South America and it's a little inconvenient to be making phone calls to credit card companies and LA Fitness corporate offices to deal with this. It's also a pain in the ass to send mail from there. But it reaches the point where despite numerous calls and letters and faxes, they charge close to $800 to my card in bogus charges.

Finally I was like "Fuck this shit" and ran a chargeback against them.