Talk Talk's Amazon Prime offer problem

rmb3971

I renewed my Talk Talk contract again April 2020 mainly because of their offer for a year's free Amazon Prime. It said I had a year to redeem it. When I tried to redeem it in early April this year the code would not work, saying it had already been used.
Amazon were most helpful but say that the code was used in November 2020 (fraudulently if it wasn't me) and there's nothing they can do about it.
I have phoned Talk Talk customer services many times since April and every time, despite staff being most polite and courteous, I have been told that the matter has/will be 'escalated' and that I will receive an email/call about it. I never do.
I'm tired of chasing it, and the length of time that each call takes while they 'look into it'.
With no email address available for them it seems I can only phone.
I have tried asking for a manager/retention team but that doesn't seem to get me any further.
I just want to start my free Amazon Prime.
I am now considering leaving Talk Talk when my contract ends in October so time is getting critical now... any suggestions please?
Thanks 

brewerdave

Have you got it in writing that you had 12 months to redeem ?? Not normal ,seems more likely that the offered expired after ~ 6 months

rmb3971

Yes, it's on an email with the code giving a redeem date of 24th April 21.