Reward card balance received less than advert applied for

[#1]

Received my reward card today but balance only £70 when I applied for plusnet it was advertised as £75 - can they reduce it after you apply?

[#2]

Hello @lennon49lennon

Thanks a lot for getting in touch and I'm sorry about this, though I've just had a look at the account and can confirm that the promotion code that the account was created with, is associated with a £70.00 gift card, not £75.00

Promo code - 2122fib8043a0rc70oe