Don't go with a company to do it for you, it's easy, it is only about three letters, each more strongly worded that you send. The templates for which are on the website. If you do have to start further procedings, that can be done simply online too. (they might try to scare you by saying they will go to court, but they never do)
They may close your account, so before you start, open another. I think loans and morgages are safe as they are under a separate agreement.
Get stuck in & Good Luck!