Marketing Emails from Plusnet - even though I said I didnt want any

[#1]

im going to post this in here, because it isn't a "problem" per se, but iv recieved an email from PN today offering me John Lewis vouchers in exchange for refferals.
I very specifically said on signup that I didn't want to opt in to marketing emails, so can someone please check that im taken off the list? thank you

[#2]

Hi severedsolo,
I've just checked your account and you were actually opted in for marketing e-mails. Sorry if you've already asked us to do this.
Please let me know if you receive any other messages from now.

[#3]

thanks adam, as i said, not an issue really, its not like you spam me with hundreds of them, i just like to keep my primary email address purely for important emails 

[#4]

Adam, Have you done a test signup to confirm that opting out of marketing does result in the opt out option being set?

[#5]

Hi Jelv,
I haven't as we're not in any doubt about this working as intended at the moment.
Test sign ups are easier said than done but will be done if anything points towards an issue.