I've requested confirmation and have only gotten it once or twice.
What I've started doing is actually just sending them their same exact terms via their corporate registered address (regardless of their instructions) with the arbitration clause and jury trial waiver and just about anything I don't agree to removed. I tell them so long as they continue to provide the services to me, that they implicitly agree to the terms I'm sending them, with any further updates requiring them to send a registered (not certified) letter.
I intentionally do not provide any way for them to identify my account except for the return address.
I figured if I ever had to go to court, one of these things would happen:
judge finds that the original terms are enforceable, which means I'm no worse off
judge finds that my amended terms are enforceable, which means it worked
judge finds both terms unenforceable and I can continue to sue them
So far, no company has ever written me back or turned off my access to the site.
I suggest everyone do this because these forced arbitration clauses are very anti-consumer and we need to start clawing back our rights.