Steers refuses to honour Voucher

On the 03 February 2021 i went in the the steers in Sarnia , at the Engen garage and wanted to redeem a voucher that i had received from ABSA rewards program . I was told by the cashier that they do not redeem vouchers at this branch and that i should try another branch . Why would ABSA partner with a franchise group that selected stores will redeem this voucher . Nothing on the voucher says "participating stores " only . I asked the cashier which store should i try , and his reply was that he didnt know , and that he was turning away many other customers who wanted to redeem their vouchers . I then contacted Steers head office and spoke to a Phume i think it was who assured me that this should not be the case and too down my details etc and promised to get back to me , well guess what today is the 8 February and Steers head office has not returned my call . In todays times where everybody is fighting to keep their businesses open Steers just doesnt give a damn .To hell with customer service it would seem . Guess which franchise i will be giving a miss the next time im ordering fast foods ???