False Adverti*****t and Dishonesty

We purchased a laptop at Incredible Connection - Centurion on 22 January 2025. The promotion stated that if you purchase the laptop, you will receive a R750.00 voucher. We received a R500.00 voucher of 7 February 2025. I queried this difference numerous times but received no reply. I think this is false advertising or dishonesty.