I signed up to Plusnet nearly two months ago on the promise of £75 cashback. I was advised on two occasions that my case would be forwarded to the marketing department to send me the email required to make a claim. Still no email. I have checked my spam and other inboxes. Found nothing. Other emails from Plusnet arrive fine.
I have the same issue! Signed up in early May from a dedicated link via MSE web site! I have kept copies and screenshots of the offer and application process. Initial calls to Customer Service have attempted to pass me on to 3rd party agencies that do not answer the phone after 30 mins holding! We should not have to deal with external agencies to obtain what was clearly advertised by PlusNet! I have now raised the matter as a complaint as advisors only sympathise but offer no solutions! Now they sit on their 10 day (Offcom) window to respond! Don't give up failing to supply the cashback is a breach of Trading Standards under the advertised offer. I have attached two documents that support the offer one from MSE web site and one from Plusnets own Application page! It's a disgrace you have to 'fight' for what is rightfully yours!!