Samsung Voucher items cant be returned , not informed correctly

I have Purchased a Sound Bar from the Samsung Online store and just recieved it today, However upon recieving the Soundbar i was not happy with it and called Samsung head office and advised that i would like to Return this product and get another one from thier website thats a bit more expensive then the one i have purchased , The agent advised that Due to the purchase done with the voucher valued at R3000 should i return the product my voucher is forfieted ??? In utter shock i may the agent aware that the package is not open it was delivered about an hour ago and i want to exchange product not even want a refund and as apart of consumer protection if product is sealed and in good condition with a Invoice Such needs to be returned , So i advised that how is it the CPA falls away if i have made purchase using a voucher ?? he could not answer

The Sound bar that i have purchased was ourchsed at a price of R2300 using the R3000 voucher however on the call i was advised that thier is no balance on the voucher and it was a once off and i was made aware , However i was not and upon going back to the voucher email in Absolutely fine print it states that if full amount not used the remainder will then fall away!!! how is this treating customers fairly now i am stuck with a sound bar that Samsung refuses to return and replace due to me using a voucher and also ****** me for the initial amount on the voucher that fell away