Samsung — Redemption issue of samsung tab s7fe keyboard cover Redemption

I have purchased samsung galaxy tabs7 fe
I am unable to redeem keyboard covers offer iCalendar samsung costumer care for more than 100 times they didn't resolve my issue they were sending me mail to send invoice ime number and screen short of error page I have sent them and they sent me a mail in return that my offer was expired on 15 February but in error page it was showing that my offer is till 1 March for 18 Feb I was calling samsung costumer care but no response plz help me out