Confusion reigns over a Plusnet referal discount email.

[#1]

I'm quite confused, which, to be fair can easily be done but I got an email from Plusnet yesterday (to my main account) saying that I'd qualified for a new signup discount and viewing this URL would give full details.
https://portal.plus.net/my.html?action=mydiscount_static_info&r_action=Current_Referrals
But I see nothing new. Looking at my bill transactions I see this:

Quote

XXXXXXX £-5.00 £0.00 12/01/2016 Credit Note Account Credit Note XXXXXXY £-5.00 £0.00 12/01/2016 Credit Note Manual spending of referral tokens by

Can anyone explain what is going on?

[#2]

The email was just to inform you of the £5 refund for referrals coming back to you.

[#3]

Sorry Chris I don't want to appear obtuse but I don't have a clue as to what that means, so I'm even more confused!

[#4]

You referred people to Plusnet and the amount of credit this has generated has reached £5. This is just us giving you that money.

[#5]

Thank you. That explains it so much better, and cleared up my confusion.