Referral discount after sign up

[#1]

I registered with plusnet and discussed it with my aunt. She was looking at different providers so didn't ask me for a referral code. She has ended up going with plusnet and has told me her username so I can get the discount, however I can't find where to use it.

[#2]

@angelicaddc You will need to contact Customer Support (0330 123 9123) as they will have to  add this manually.