What a coincidence, a friend has lotto scratch cards that wouldn’t scratch on 3 occasions, he took it to the shop and they typed in the serial number and hey ho, it was a winner, this happened on two other occasions and he’d one £5 k, £1500 and £750 or so,this seems a ploy by big companies to have winning scratch cards but purposely hinder your attempts to see if you’ve won so they don’t have to pay out.
My guess is you’ve won so Phone them tomorrow and quote the serial number to them. Good luck! :)