Re: £50 cash back email
Cashback rewards are normally an automatic process, the question is did you sign up for the cashback online through PlusNet or was it through an external reward site? If it was through PlusNet Online cashback would be expected to be paid after one billing cycle, between 30 and 45 days I would have thought. If the cashback was from an external cashback site then you could be looking at 120+ days to receive confirmation of funds being paid.
Hope that helps, be it not the immediate answer your looking for. If you haven't received the funds credited to your account after 45 days then a phone call to customer services would surely sort it.