How do I claim my 35 pounds cash back for joining with Plusnet?

[#1]

I have just set up anew account with Plusnet. One of the perks of the package is an offer of 35 pounds cashback. I have been told I actively have to claim for this but have not been told how. Please can you tell me how to claim for this? thank you

[#2]

Once your first service (broadband or phone) goes active with us we'll send you an email within 10 days, this will have a link to claim and fill in some information.

[#3]

Thank you very much for speedy response