We signed up as a new customer for BT Fibre broadband on 28-06-20 and it was activated on 13-07-20. On 04-09-20 we checked our account but there was no rewards card. We phoned the complaints line (as no available email address for bt). We explained the problem to the bt person and were asked a number of questions and suggested that it may have been because we signed up via a third party. We did not believe this was the case as the application was completed on the bt website. The bt person advised a voucher could be provided in place of the reward card, which we expected to be for the value of £80 (the full offer value stated).We have however today received a notification by email that a voucher to the value of £50 only will be sent. This is an obvious shortfall of £30 and not adhering to the offer made on signing up. The value of £80 was quiet clearly stated upon signing up and was advertised clearly on a number of websites and within the offer qualifying period. As it is preferable for responses to be in writing we would be grateful for help from the forum to resolve this.