I wouldn't worry too much about it. It's not pleasant, but they have no power to force you to pay any money at all.
Are you currently heading towards an IVA? If so, you could speak to them when they phone and just explain what you are doing. Be polite, say your piece and then put the phone down. Don't be bullied.
As for the debt collector, you don't have to answer the door to them, but again you could just explain your position and then close the door.
They have no powers to come into your house.
Sharing from experiences of dealing with debt
The greatness of a man is not in how much wealth he acquires, but in his integrity and his ability to affect those around him positively.
Bob Marley. http://kallis3.blogs.iva.co.uk
