What to do next

Hi all
First time post so bear with me.Can anyone help
I recently had the platte media icon appear on my desktop, and after opening the programme, discovered that (so they say) I have signed up to their service, and now owe them Â£29.99 for the privelidge. I did not sign up for this, and so I called the number on the screen, to "discuss my bill". They insisted that I had signed up, but said that I could receive an uninstall programme to remove the software from my PC. So - and I know some of you will be screaming NOOOOO!!! - I gave my name and address for them to send this software. It was then that I discovered this forum, and a post which started a while ago, regarding Platte Media, and how to remove the software myself. This I have successfully done, but today in the post arrived a letter from Platte Media. Page 1 was a "unique Key Code" and instructions to visit their website, enter the code ( my Postcode with 32 digit code)
Page 2 detailed their original registration process. Page 3 was my "Bill", and page 4 was telling me the time and date and I.P address used to access their site.
Reading the old post regarding this company, I don't know what to do. Now that they have my details, do i just pay, or ignore the whole thing. I'm quite worried about what to do next, and I hope someone can offer up some advice. It would be greatly appreciated

thanks
Kev.T