Vodacom - Ultra Note 20 with special (A **** or WHAT?)

We purchased the new Note 20 Ultra with the special of an e-voucher to the value of R4000.00. Apparently Vodacom gives e-vouchers which enables a person to purchase from their online samsung store. When using the voucher, the site does not allow you to redeem the voucher, however, ask you to make payment with your debit or credit card. We notified Vodacom about this concern, however a week later they have no solution, but to send you in . Is this a **** ? Why can't you even resolve your issues you have on specials you have advertised.