Vitality cash back delay

I am a Vitality member on diamond status and during the lockdown I qualified for a 30% discount on Healthy Gear items. I bought a Polar Watch on the 20th of June, but still haven't received my discount cash back. First I had to prove that my watch do qualify as per their and total sport's website. Then I had to submit my cash slip after which they agreed that the watch qualifies. Numerous emails get the same computer generated response - "thank you for your patience, but your query has been escalated to back office". This is not complicated, why is back office struggling with it?? If you don't want to deliver on your promises - tell me, so I can decide what i want to do about it.