How do I disconnect one ask.fm account from my twitter and then add a new account?

[ashley]

I didn't know I had a ask.fm already set up to my twitter and I can't log in to disable it. I have a new ask.fm with loads of questions to answer and it won't post because it says I'm already connected to another account! How do I go about fixing this.
FYI this is what it tells me every time I try to post my answers to twitter.

Could not connect with your current Twitter account, because it's already linked to another Ask.fm profile.
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[xoxo-gossip-girl]

go to https://twitter.com/settings/applications and revoke access for ask.fm and re-connect with the account you want