They are the same company as Boston Sports Clubs and H had no problem cancelling. I would ask to speak to a manager. He he called member services or did he go into the club to cancel?
If I call my bank and tell them there are unauthorized drafts on my account, they will credit the charges back to me and send an affidavit to the company that made the drafts. I had the issue when someone was drafting my account (using the actual checking account and routing numbers) for freaking Verizon Internet bills.
I'd call your bank and see what they can do. They may refund you, and they may be able to do something to stop the gym from being able to take money from you going forward (changing the account number might do that).
Shaming them on twitter and/or FB may help.
Who is your husband talking to when he calls? I'd try to reach someone corporate rather than the yoyos who work at the gym itself. Mention all of the times you've talked to people with as much detail as you can (names/dates/etc.). If that doesn't work, send a certified letter.
This is just what I would do as a normal person -- not legal advice.